2011 EMC Test & Design Guide

TM

2011 EMC Test &

Design Guide technologies Grounding ......................................... 68 Lightning, Transients & ESD...... 52, 84 Shielding............................................ 68 Testing & Test Equipment.................. 8

industries & applications Design................................................. 68 Military................................................ 84 Smart Grid.......................................... 60 Standards............................................. 8

directories 2012 EMC Test Lab Directory........... 26 Consultant Services......................... 31 Suppliers............................................ 40

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In Europe, call ar United Kingdom 441-908-282766 • ar France 33-1-47-91-75-30 • emv GmbH 89-614-1710 • ar Benelux 31-172-423-000 Copyright © 2011 AR. The orange stripe on AR products is Reg. U.S. Pat. & TM. Off.

contents 2011 ON THE COVER: Artistic rendering of a probability function graph (Page 49).

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TESTING & TEST EQUIPMENT Why So Many EMC Standards? ....................................8 steVE hayes, TRaC Global; Jack McFadden, Wyle Laboratories; Steve o’steen, Advanced Compliance Solutions, Inc.; KenNETH Wyatt, Wyatt Technical Services; and DAVID ZIMMERMAN, Spectrum EMC Consulting

Automotive RF Immunity Test Set-Up Analysis: Why Test Results Can’t Compare.................................16 MART COENEN, EMCMCC bv; HUGO PUES, Melexis NV; and THIERRY BOUSQUET, Continental

Time-Domain EMI Measurement System Up to 26 GHz with Multichannel APD Measuring Function ..............42 Hassan Hani Slim, christian Hoffman, Stephan Braun and ARND FRECH, gAUSS Instruments GmbH; JOHANNES A. RUSSER, Institute for Nanoelectronics, Technische

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surge & transients

26

SPECIAL FEATURE

2012 EMC test lab directory More than 300 EMC Test Laboratories, arranged geographically, with details of services offered and contact phone numbers, are presented as a quick reference guide to EMC testing services.

Transient Voltage Suppressors (TVS) for Automotive Electronic Protection .....................................................52 SOO MAN (SWEETMAN) Kim, Vishay Intertechnology, Inc.

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emc test & design guide 2011

contents 2011

60

84

68

SMART GRID EMC and the Smart Grid...............................................60 William A. Radasky, Metatech Corporation

DESIGN Designing Electronic Systems for EMC: Grounding for the Control of EMI...........................................................68 William G. DUFF, SEMTAS Corporation

Electrostatic discharge

Departments

06

Editorial

26

Test Lab Directory

96

Index of Advertisers

A Comparison between Gelatinous and Tacky Coated Type Packaging Carriers.................................................84 Robert J. vermillion, RMV Technology Group, LLC, and DOUG SMITH, DC Smith Consultants InterferenceTechnology—The EMC Directory & Design Guide, The EMC Symposium Guide, and The EMC Test & Design Guide are distributed annually at no charge to qualified engineers and managers who are engaged in the application, selection, design, test, specification or procurement of electronic components, systems, materials, equipment, facilities or related fabrication services. To be placed on the subscriber list, complete the subscription qualification card or subscribe online at InterferenceTechnology.com.

ITEM media endeavors to offer accurate information, but assumes no liability for errors or omissions in its technical articles. Furthermore, the opinions contained herein do not necessarily reflect those of the publisher.

ITEMTM, InterferenceTechnology™—The EMC Directory & Design GuideTM, and Interference Technology.comTM are trademarks of ITEM media and may not be used without express permission. ITEM, InterferenceTechnology—The Annual EMC Guide, The EMC Symposium Guide, The EMC Test & Design Guide and InterferenceTechnology.com, are copyrighted publications of ITEM media. Contents may not be reproduced in any form without express permission.

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emc test & design guide 2011

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from the editor We Are the (Engineering) world

E

lectromagnetic interference knows no borders, so an international collaboration seems to make the most sense when it comes to tackling the issues confronting the EMC industry, from testing standards to job qualifications. Of course, this sentiment is also logistically impractical and clearly not a reflection of reality, but there are some areas where an international approach is being applied.

Take, for instance, Germany’s efforts to reverse its engineering shortage.

About 76,200 engineering jobs are vacant in Germany, according to a recent assessment by the Association of German Engineers (VDI), and the nation’s leaders have employed two approaches to address the problem: facilitating cross-border recruiting and targeting the promotion of young talent in the field.

To make it easy for engineers to move around Europe, engineering associations and other groups across Europe are working with the European Commission to launch the new Engineering Card. The card, which German engineers can apply for now and other countries are planning to launch, provides standardized information about the engineer’s qualifications and skills for greater transparency. Setting comparable standards helps remove barriers in changing jobs between individual member states and emphasizes professional mobility.

To accomplish the second aim of increasing the numbers of young people entering the field, the German engineering associations are spearheading several promotional initiatives targeting young students and are also lobbying lawmakers to establish a nationwide educational policy for teaching technology in primary and secondary schools.

Such an approach, useful for all countries, is also being expanded to the recruitment of girls and women, populations that are still under-represented in engineering. More and more initiatives are encouraging young women to be enthusiastic about technology and not be guided by old gender roles. As more role models in the form of professional engineers report on their career development in lectures, workshops and information sessions around the globe, the message will continue to sink in – to everyone’s benefit.

For the first time this year, Interference Technology is also expanding its scope, by including international listings in its EMC Test Laboratory Directory, which begins on Page 26. Common sense tells us that most engineers and designers prefer to use local testing facilities so our easy-to-use directory of labs and their services are grouped alphabetically by geography.

However, this first effort is far from complete. If you own or work for an EMC test lab and we have missed you or omitted one of your services, please let us know. We’ll continue to update the digital edition of the directory throughout the year. You can e-mail your additions, revisions, and suggestions to me at slong@interferencetechnology.com.

Sarah Long Editor S u b s c r i p t i o n s

ITEM, InterferenceTechnology—The EMC Directory & Design Guide, The EMC Symposium Guide, The EMC Test & Design Guide and The Europe EMC Guide are distributed annually at no charge to engineers and managers who are engaged in the application, selection, design, test, specification or procurement of electronic components, systems, materials, equipment, facilities or related fabrication services. Subscriptions are available through interferencetechnology.com.

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2011 EMC Test & Design Guide Editor Sarah Long Editorial Assistant Cait O’Driscoll Graphic Designer Ann Schibik Marketing Specialist Jacqueline Gentile Business Development Manager Bob Poust Business Development Executives Tim Bretz  Daryl McFadyen Leslie Ringe  Jan Ward Administrative Manager Eileen M. Ambler Administrative Assistants Karen Holder  Irene H. Nugent Product Development Manager Helen S. Flood

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Publisher Emeritus Robert D. Goldblum President Graham Kilshaw Publisher Paul Salotto USA 1000 Germantown Pike, F-2 Plymouth Meeting, PA 19462 Phone: (484) 688-0300 Fax: (484) 688-0303 info@interferencetechnology.com www.interferencetechnology.com china, taiwan, hong kong Beijing Hesicom Consulting Company Lily Liu +86-010-65250537 E-mail: service@leadzil.com JAPAN TÜV SÜD Ohtama, Ltd. Midori Hamano +81-44-980-2092 E-mail: m-hamano@tuv-ohtama.co.jp ITEM MEDIA endeavors to offer accurate information, but assumes no liability for errors or omissions.

Information published herein is based on the latest information available at the time of publication.

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ITEM TM, InterferenceTechnology™ and InterferenceTechnology.comTM are trademarks of ITEM MEDIA and may not be used without express permission. ITEM, InterferenceTechnology and InterferenceTechnology.com are copyrighted publications of ITEM MEDIA. Contents may not be reproduced in any form without express permission.

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testing / standards

W h y S o M a n y EMC S ta n d a r d s ?

Why Are There So Many EMC Standards?

Industry experts ponder this and other standards-related issues

Steve Hayes TRaC Global, Worcestershire, United Kingdom

JACK McFADDEN Wyle Laboratories, Huntsville, Alabama, USA

STEVE O’STEEN Advanced Compliance Solutions, Atlanta, Georgia, USA

Kenneth Wyatt Wyatt Technical Services, Woodland Park, Colorado, USA

David zimmerman Spectrum EMC Consulting, Eagan, Minnesota

O

ctober 2011 sees the end of the transitional period from previous versions of EN55022 to the latest version, which now requires testing above 1 GHz for the first time. At the same time, beginning of October 2011, the Official Journal of the European Union listing the harmonized standards for the EMC Directive has also been updated. Notable (and predicted) is the inclusion of both generic standards for emissions (EN61000-6-3 and -4). Both these standards now include emission requirements above 1 GHz in the same way that EN55022 has. While the transitional period for EN55022 has just ended, it has just begun for the generic standards, making them mandatory only from January 2014. (See box on Page 10 for more on EMC testing above 1 GHz).

This issue recently inspired Steve Hayes, CEng MIET, managing director for EMC 8

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and safety at TRaC Global Ltd., to pose a question to his colleagues on LinkedIn, asking: Is this transitional period, where a manufacturer can choose to use either standard to demonstrate compliance to the EMC Directive, too long? After all, the product churn in today’s world is largely much faster than this and, hence, manufacturers may see at least another product launch before above-1 GHz test requirements are required. Equally, the protection of the RF spectrum will be under pressure while millions of new products enter the market without any control of their electromagnetic emissions for another two years.

Interference Technology invited Jack McFadden, senior project engineer at Wyle Laboratories; Steve O’Steen, EMC director at Advanced Compliance Solutions, Inc.; Ken Wyatt of Wyatt Technical Services; and David Zimmerman, president of Spectrum EMC Consulting, to expand on this and other questions posed by Hayes.

HAYES: Is the transitional period from old to new standards too long? zimmerman: This is an excellent point, and a shortcoming of the European Union EMC compliance system, in my opinion. In fact, there are other product family standards that will lag behind in the emission requirement above 1 GHz, and some may not change in the next 10 years. In answer to the question, in many cases, the time between the need for testing, and the date that a standard exists that requires testing, is too long to ensure that EMC conflicts emc test & design guide 2011

testing / standards

W h y S o M a n y EMC S ta n d a r d s ?

are avoided.

O’STEEN: The “product churn” cycle is a significant variable which will vary widely across all industries so I would not dismiss it so easily. There needs to be balance between what’s economically prudent for the manufacturer and technically responsible in the interests of EMC. Equipment manufacturers are still held responsible for any interference caused by their equipment and are forced to resolve field complaints whether the interference is above 1 GHz or not.

I think the current two-year transition is adequate to allow the manufacturer to complete the redesign and address any compliance concerns during preliminary reviews.

Large manufacturers who have their own compliance labs and permanent compliance staff are aware of the coming requirements and will typically get a jump on any issues which would be necessary due to their broad product line.

Smaller manufacturers with fewer internal compliance resources will have to resort to alternate means via their local independent compliance lab, which would likely introduce some additional delay during the transition. From the perspective of the small independent compliance test lab, this particular example (EN61000-3 and -4) is not a concern, considering most labs have already completed the site validation above 1 GHz for EN55022:2006 + A1:2007.

Any new revision of a standard that requires radical changes in the way a test is performed or in the way equipment is being used or introduces the need for a new category of test equipment could certainly require a significant amount of the transition time.

STEVE HAYES is managing director for the EMC and Safety business of TRaC Global in Worcestershire, United Kingdom, and has been involved in EMC and product approvals for 19 years. In addition to being the UK principal expert on EMC standardization of Industrial, Scientific and Medical (ISM) products, he is also the convenor of CISPR/B/WG1 who has the responsibility of writing the International standard, CISPR 11. Hayes wrote the CE marking annex to the UK’s defense EMC standard, and was co-convenor of CENELEC TC210/ WG9, responsible for writing a guide on approval of military systems with commercial requirements.

JACK McFADDEN is senior project engineer at Wyle Laboratories in Huntsville, Ala., where he provides customer support in the field of electromagnetic interference/compatibility: generate quotes, develop budget, test schedule, create test plans/test procedures/ reports, technician work instruction/direction, software validation, training, and mitigation as needed. McFadden served as chair of the Huntsville chapter of the IEEE EMC Society in 2010-2011. He a certified EMC engineer through iNARTE. STEVE O’STEEN is EMC Director at Advanced Compliance Solutions, Inc. and is responsible for EMC-related issues and support at all ACS compliance facilities. O’Steen has worked in EMC and Product Safety disciplines for 20 years, which were divided among independent compliance facilities as well as on the manufacturing side. Currently, O’Steen devotes much of his time to standards and equipment research, test plan and test procedure generation, EMC training and compliance mitigation issues. He also takes the lead role when “out-of-scope” requests are issued requiring standards and equipment research.

wyatt: From the manufacturer’s and test lab’s point of view, a two to three year transition period is good in that it provides a defined length of time to procure new equipment (typically, long lead times to develop budgets, evaluate equipment, etc.), and update test procedures. More importantly for the manufacturers, because the EU does not allow “grandfathering” of existing products, this provides sufficient time to re-qualify existing products with longer lifetimes. Not all product lives are measured in months.

KENNETH WYATT is senior EMC engineer at Wyatt Technical Services, LLC, in Woodland Park, Colo. Wyatt has worked as a product development engineer for 10 years at various aerospace firms on projects ranging from DC-DC power converters to RF and microwave systems for shipboard and space systems. He spent most of his career as a Sr. EMC engineer for Hewlett-Packard and Agilent Technologies. A prolific author and presenter, he has written or presented topics, including RF amplifier design, RF network analysis software, EMC design of products and use of simple tools and techniques to troubleshoot radiated emission, ESD and RF immunity.

HAYES: Do you think the limits in EMC standards are too onerous? You can put a mobile phone (acknowledged as generating a high RF field) next to a PC or mobile electronic gadget without electrical interference occurring.

Based on this, could the limits be increased? wyatt: The example specified may be true in some cases, but not necessarily for all products. For example, products with sensitive analog circuitry, such as measuring equipment, medical products and sensors, are very likely to be affected by mobile phones and two-way radios or other ambient signals.

DAVID ZIMMERMAN is an EMC engineer and president of Spectrum EMC Consulting in Eagan, Minn. Zimmerman offers consulting for the improvement of operations at EMC laboratories by increasing the accuracy of measurements, and streamlining processes resulting in higher efficiency; training in the performance of EMC testing and EMC standards at customer sites; coordination and oversight of product testing at any EMC test facility; writing test procedures and reports to a wide variety of EMC standards; and generating technical files for EMC Directive requirements.

zimmerman: I would have to agree with the general consensus that the limits are properly set. A lot of work goes into determining what the limits should be. In fact, there are standards committees that are hard at work to make testing to these limits more thorough. Things like testing all sur10

interference technology

emc test & design guide 2011

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rf/microwave instrumentation Other ar divisions: modular rf • receiver systems • ar europe USA 215-723-8181. For an applications engineer, call 800-933-8181.

In Europe, call ar United Kingdom 441-908-282766 • ar France 33-1-47-91-75-30 • emv GmbH 89-614-1710 • ar Benelux 31-172-423-000 Copyright © 2011 AR. The orange stripe on AR products is Reg. U.S. Pat. & TM. Off.

testing / standards faces of an EUT, and bore sighting of the antenna above 1 GHz for example.

O’STEEN: No. In the example above, you give one possible interference source and one receptor for which general rules should not be based. Compliance levels and performance criteria should be based on historical data and sound engineering judgment and should apply to new standards as well as revised standards. Again, a balance must be achieved between the manufacturer’s desire to market their products and their compliance responsibilities.

HAYES: Why are the automotive EMC standards so different from commercial ones given that the environment is the same? The basic premise that in a vehicle electrical noise is generated by the spark ignition system and the limits are set based on interference to only the FM radio band seem somewhat dated. mcfadden: I need to start with the question’s premises that “given that the environment is the same”. I do not agree with this premise. The environment is different. It would be easier if everything was black and white, if one size could really fit all. The world exists with various shapes, sizes and colors. There are vast environmental differences between the automotive and most commercial industries. One example, an engine control unit (ECU) operating temperatures are minimum of -40°C to a maximum of +150°C, reference SAE J1211, Table 1. The typical commercial products have a much more benign temperature operating range. I will not take the time to go into detail to discuss the commercial vs. automotive industry differences within the power bus, grounding schemes and etc. Just keep in mind, temperature itself alters the behavior of electronic components.

Just as there are differences within the thermal environment, there are also differences within the electromagnetic spectrum. The electromagnetic spectrum varies from one location to another location. As an experiment, take a look at analog compass as you pass over a bridge or go through a 12

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W h y S o M a n y EMC S ta n d a r d s ?

EMC Testing above 1 GHz For more infor mation on EN55022:2006 +A1:2007 and its new requirements, see Steve Hayes’ article, “EMC Testing above 1 GHz: The Deadline Looms,” in the Interference Technology 2012 Europe EMC Guide. Download a pdf at www.interferencetechnology.eu.

You will find the article under the United Kingdom section.

toll booth. The needle in the analog compass will lose magnetic north for a brief period then return to normal after the magnetic disturbance has passed. Electronic compasses may also be affected but it depends on their update rate, time within the disturbance area and the embedded software used within the electronic compass. The premise that the vehicle noise is limited to just concerns from the ignition firing (spark) effect on the radio is no longer true. It has not been true since the dawn of the electronic ignition. The electrical/electronic sub-components, sensors and modules are placed all over the vehicle. Windows open through the activation of a switch. The vehicle doors lock or open with press of a button. Airbags deploy when the vehicle system senses a crash. Some vehicles can actually speak to you, give you directions and make phone calls. The vehicle technology has drastically increased over the past few decades. As the technology has increased, so has the complexity of the vehicle, causing the electromagnetic compatibility concerns to grow. For example, airbags deployment must be during a crash and the airbags should not deploy as you drop off someone at the airport. Yet the automotive technology successes have been so pervasive that the vehicles’ quality and reliability are often taken for granted.

Even if we were to visit “Alice in Wonderland” and the “environment” was truly the same you need to answer this question. What is the risk if there is a susceptibility condition?

Going back to the case of the analog

compass; you will see a momentary deviation from normal operation with the compass (product) returning to normal operation after the disturbance has passed. It may be inconvenient but it is not life threatening. Now what if the automobile’s operation was affected (susceptible) to its environment? What is the worst possible outcome? The vehicle accelerates without driver action and crashes into another vehicle.

So the risk between most commercial products and automotive industry is different. The automotive standards need to be set higher to account for this risk (and they are). If we were to prescribe to “one size fits all” then we would need to raise the universal standard to the represent the highest (worse case) risk. We would be, in effect, adding cost to the commercial products without value. The value the individual standards have is that they permit the industry to address their individual needs. You tailor your product requirements to meet needs of its intended environment in order to reduce the risk. Or in other words, the individual standards are designed for safe and proper operation of the product within its intended environment. wyatt: I would disagree the environments are the same for office versus field. More and more automotive products today use “fly by wire” technology with a myriad of microprocessor-based subsystems. Hey, even the transmission on my truck has its own processor! Because rapidly moving vehicles can quickly turn into deadly weapons, safety standards (and corresponding EMC standards) are necessarily more stringent. There have been numerous incidents where poorly shielded vehicles have developed operational issues (braking, cruise control, etc.) due to aftermarket two-way radios being installed. zimmerman: This appears to be another case where standards take a path of their own based on the committee that is writing them. These standards are driven in large part by the manufacturers and not the consumers. From my limited experience in this area, it seems that as long as the equipment emc test & design guide 2011

testing / standards

W h y S o M a n y EMC S ta n d a r d s ?

category. Getting all of the industry experts to agree on common limits, performance criteria and methods would not be feasible. All of these Product Specific Standards are typically not written exclusive to one environment but are focused on a category of equipment but more importantly, it’s the performance criteria that separates these categories.

Could you imagine a Product Specific Standard that would apply to all devices employed in a residence, taking into account for the variety of test levels, variety of test methods and performance criteria would result in an unnecessarily complex and unmanageable standard.

In addition, standard writing committees are constantly addressing the need to revise current Product Specific Standards in an effort to address compliance concerns for new technologies that happen to fall within the scope of that standard. These new environment-based standards would be in constant revision and release and would continue to lag behind the technology curve. I can certainly see the appeal of the environment-based standard system, but I don’t think each of these standards could effectively address the specific requirements and concerns associated with each product type found in that environment.

installed in vehicle does not interfere with the other installed equipment, there is no need for concern about interference beyond that which is known.

HAYES: Why are there so many EMC standards? Surely the environment is the same whether you use a toaster or PC in the home, yet the test standards (and in some cases, limits) are different. Could a ‘one standard fits all’ based on environment be produced? Imagine the savings that could be made not having to investigate which standard is the most appropriate. wyatt: I believe there has been a trend in harmonizing many standards. I know this was moderately high on our agenda when I was serving on a standards working group.

There will always be differences in certain products, I suppose. From a manufacturer’s point of view, it’s sometimes difficult to figure out the appropriate standard to use for a given product type, however, I’ve found that most test labs or consultants can assist with this. When all else fails, there ARE the generic standards.

O’STEEN: In my opinion, this would be very difficult to accomplish based on the engineering time and expertise devoted to tailoring the Product Specific Standards to address potential issues and performance criteria for each product

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mcfadden: The environment is not the same. The environment of a toaster and personal computer (PC) in the home has some similarities but they are truly different upon closer inspection. The similarities are the utility power and the general location (home). Most toasters do not have intentional frequency generators within the circuitry. The typical toaster has one input power cable connecting it to the power bus. They are more electrical in design rather than electronic. The PC typically has several intentional frequency generators within its circuitry. It is a digital (electronic) device. The PC has multiple cable connections bringing it to printers, Ethernet, monitors and etc.

It can generate interference over a larger spectrum than the typical interference measured from a toaster. The PC can also be affected by interference from a larger spectrum than a typical toaster. The toaster and PC may share the same home, but its reaction and its impact to its environment is completely different.

If the environment is not the same and the products’ function/operation are not the same is it possible to make one universal standard? I believe all things are possible, but many are improbable. It is possible to generate one universal standard. The question that should be answered is what would be the cost of the universal standard?

Would the universal standard be a value added or will the universal standard generate additional cost without benefit? It comes down to determining acceptable risks.

The regulating bodies and industry have determined that individual standards that tailor products to specific categories are the most effective way to keep the desired product quality while keeping the cost aligned. This leads to a great deal of confusion when you are searching for the appropriate standard. Many times the governing standard will reference another common standard to require

emc test & design guide 2011

testing / standards

INT E RF E R E N C E T E C HNOL O G Y

certainly get at least as many different standards as there are groups writing them.

the product to be tested with these specific tests at these specific levels (limits) while using this other standard’s methodology. This is true for the EN 55011, Industrial, scientific and medical (ISM) radio-frequency equipment – Electromagnetic disturbance characteristics – Limits and methods of measurements; and EN55024, Information technology equipment – Immunity characteristics – Limits and methods of measurement and a host of others.

If you wanted to develop one universal standard then you would require acceptance and input from all of the regulating bodies as well as all of the industries. The industries’ concerns regarding their products are highly exclusive.

Their concern is only for their particular product(s). Now consider the logistics of bringing all the industries and all the regulating bodies, then have them willing to be inclusive. You are going against human nature and it is going to be painful. If you have had any experience in attempting to achieve consensus with a small body of people, imagine the challenge of getting a global industries and their regulating bodies to agree. I am not saying it is impossible. I believe it could be done. I just believe it is improbable.

HAYES: Will ISO and IEC ever align their test methods, limits and procedures? Surely we don’t need multiple ways of assessing the same issue – electrical interference? wyatt: Well, I sure hope so, for the sake of everyone’s sanity. zimmerman: The likelihood of this happening is not great.

Peace in the Middle East has a similar chance of happening in our lifetime. Standards writing bodies have a lot of pride and defend their positions with great zeal. If you check the “About ISO” Web page, you will see that it starts by stating “ISO is the world’s largest developer and publisher of International Standards. Size matters. If you go to the “About IEC” Web page, you will find this statement: “The International Electrotechnical Commission (IEC) is the world’s leading organization that prepares and publishes International Standards for all electrical, electronic and related technologies.” So the IEC is the world leader. You can see where these two groups will not want to concede their ranking. Would it make sense to align these test methods?

The general consensus would be a resounding “yes”, but this does not mean that it will happen anytime soon. n

zimmerman: The problem is that there are many differing opinions about what tests and limits are needed for a given environment. As long as there are two or more groups writing a standard for a given environment you will most

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testing & test equipment

A u t o m o t i v e RF I m m u n i t y Te s t S e t - u p A n a ly s i s : W h y Te s t R e s u lt s C a n ’ t C o m par e

Automotive RF Immunity Test Set-up Analysis: Why Test Results Can’t Compare

Mart Coenen EMCMCC bv Eindhoven, The Netherlands

Hugo Pues Melexis NV Tessenderlo, Belgium

Thierry Bousquet Continental Toulouse, France

ABSTRACT hough the automotive RF emission and RF immunity requirements are highly justifiable, the application of those requirements in an non-intended manner leads to false conclusions and unnecessary redesigns for the electronics involved. When the test results become too dependent upon the test set-up itself, interlaboratory comparison as well as the search for design solutions and possible correlation with other measurement methods loses ground. In this paper, the ISO bulk-current injection (BCI) and radiated immunity (RI) module-level tests are discussed together with possible relation to the DPI and TEM cell methods used at the IC level.

Keywords: Bulk Current injection (BCI), Radiated Immunity (RI), Direct Power Injection (DPI), TEM cell, wire harness, automotive module, Electronic Control Unit (ECU) and Electronic Sub-Assembly (ESA)

T

I. INTRODUCTION The increasing use of electronics in vehicles 16

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requires a very high level of reliability to assure the safety of the vehicle occupants as well as all other road users. Aside all mechanical vibration, thermal and moisture requirements, the new sensors and active actuators used have to be robust against the electromagnetic threats which originate from causes both within and around the vehicle. Already in the past, RF emission and immunity requirements were set by ISO, in particular by TC22/SC3/WG3 who deals with electromagnetic interference. Due to the growing use of these requirements, it is increasingly important to avoid faulty application and interpretation of them. This has a two-fold drawback: • Module compliance doesn’t necessarily mean in-vehicle compliance after integration and • Compliance to over-testing over a large range has an inverse impact on economics The playing field is wide and involves car-manufactures as well as the Electronic Control Unit (ECU) and Electronic SubAssembly (ESA) manufactures, down to the silicon design to achieve a more integral economic solution.

New vehicle developments like using non-conductive composite materials, ‘zero emission’ exhaust requirements for combustion motors, the introduction of the hybrid motor or full electric vehicle put an ever higher burden on economics as well as safety reliability for the electronics used.

The RF immunity requirements have therefore been extended beyond the 30 V/m, ©2011, University of Zagreb

emc Test & design guide 2011

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A u t o m o t i v e RF I m m u n i t y Te s t S e t - u p A n a ly s i s : W h y Te s t R e s u lt s C a n ’ t C o m par e

The calibration of the BCI clamp is described in detail in the latest version of the standard [2, 8, 9].

With the BCI test, there are two options implemented: ‘open loop’ and ‘closed loop’. With the ‘open loop’ test, the voltage coupled into the calibration test jig to achieve the required current through a 50  load (where the opposite side of the test jig is loaded with 50  as well) is recorded and the forward power level is maintained during the immunity test while the injection probe is positioned at the three harness locations.

With the ‘closed loop’ test, the RF current is increased up to a level where the DUT fails or the current limit or the forward power limit is reached: 4x the nominal RF power as used during calibration to meet the induced current requirements.

However, the ‘open loop’ test method was intended to apply for non-grounded DUTs and the ‘closed loop’ should apply for grounded DUTs only (as RF currents will flow intentionally).

Applying a closed loop bulk current of 100 mA into a insulated sensor with a capacitance to the reference plane of 20 pF at 3 MHz would require an output power of nearly 1500 Watt from a 50  RF generator when no power limit is applied. Applying the open loop test would only require 0,5 Watt, a difference of 35 dB in RF power.

The second pitfall comes in three: the length of the harness, the equivalent RF termination at both ends of the harness and the BCI clamp itself.

The cable harness above the reference plane represents a transmission line with a characteristic impedance of 150 – 200 , Figure 1. Even in the ideal case when the cable harness is only terminated by two ANs to ground, being equal to 25  in common-mode, there is a serious mismatch between the harness transmission line impedance and the ANs in parallel.

When a capacitor to ground is used for one of the (signal) lines in the load box circuit, the harness termination impedance mismatch will even be higher and standing waves over the harness will result.

Figure 1. The characteristic impedance calculation of a cable harness over a metal plate (Agilent AppCad (freeware)).

in the 20 – 1000 MHz frequency range, as specified in the European Automotive Directive 2004/104/EC with its many amendments [1].

Most car manufacturers use extended immunity requirements downwards from 20 MHz to 150 kHz, typically by using the bulk current injection (BCI) test method. Where the highest level according the standards is 100 mA, levels up to 600 mA are already specified by some car-manufacturers. BCI test set-up drawbacks and pitfalls are described in chapter II. 100 V/m has been set as typical radiated immunity (RI) requirement for non-safety related ECU/ESA and 200 – 600 V/m for those ECU/ESAs which are safety related. The frequency range for the radiated emission and immunity of applications has been extended upwards from 1 GHz to 2 or even 6 GHz. This will be elucidated in chapter III. In chapter IV, the necessary conditions to obtain possible correlation with IC test methods will be given and conclusions will be given in chapter V. II. BCI TEST SET-UP The BCI test set-up, according ISO 11452-4 (2005) [2] is specified in the frequency range 1 – 400 MHz. The BCI test defines that the cable harness length = 1 ± 0,1 meter and it shall be positioned at 50 mm above a metal reference plane at 0,2 meter from the front edge of the metal plated table, see figure 1. The metal plated table is defined 1,5 meter wide and 0,9 meter high positioned above a conductive floor. The battery shall be connected through an artificial network (AN, also known as Impedance Stabilizing Network: ISN) with an impedance of 50  // 5 H but this network is only defined in the frequency range 0,1 - 100 MHz. An RF-impedance undefined load simulator box is prescribed in-between the cable harness to the DUT and the ANs. The BCI probe shall be placed at distances, d, from the connector of the DUT; 150, 450, 750 ± 10 mm for the openloop method and 0,9 ± 0,1 m for the closed-loop method. If a current measurement probe is used during the test it shall be placed at 50 ± 10 mm from the connector of the DUT. 18

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Figure 2. Simulated BCI clamp turns ratio effect on resonances 1) 1:5, 2) 1:2, 3) 1:1 load box impedance is 1 , DUT is floating, open loop test.

emc Test & design guide 2011

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On the opposite side of the harness, the DUT will be left floating or grounded. In either case, another ideal condition for resonances. However, these harness resonance frequencies are fully determined by the cable harness length which might include the wiring inside the load box up to the ANs. The third item in this equation is the BCI clamp itself as the turn ratio between primary and secondary of this ‘transformer’ determines the resistive loading of the harness loop. Dependent on the frequencies designed for, the BCI clamp turns ratio also varies between manufactures, this between 1:1 and 1:5 which alters the equivalent damping resistance between 50 and 2  (when excluding the RF losses of the clamp itself).

The length of the cable harnesses tested with varies between 1 - 2 meter determined by the specification of the end-user i.e. car manufacturer and has typically the same topology as used with the RI test set-up.

In the simulated results of figure 2, the DUT’s RF voltage towards the reference plane is given from a ‘floating’ sensor under the condition when the load box represents low RF impedance at the end of the harness. 0 dB represent the nominal voltage. Due to the open-ended transmission line, the induced voltage appears in full at the lower frequencies.

This DUT to reference plate voltage, divided by the distance gives the local E-field strength. Excesses over 30 dB both above and below nominal can be noted which are also mea-

interferencetechnology.com

Figure 3. Measured BCI clamp turns ratio 1:2; load box impedance is 1 , DUT is floating, open loop test, nominal level is 100 dBV.

sured from the test set-up and can also be seen in real RF immunity test results, figure 3. The resonances occur at all harmonics of where the harness length equals n/4. When the cable harness is 2 meter long, the first resonance occurs at 37,5 MHz, see figure 3.

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A u t o m o t i v e RF I m m u n i t y Te s t S e t - u p A n a ly s i s : W h y Te s t R e s u lt s C a n ’ t C o m par e

the cable harness characteristic impedances as well.

Only for the artificial BCI and RI test set-up, the cable harness will be used at 50 mm apart from a metal reference plane i.e. vehicle frame. In real cars, where the harness is routed against the vehicle’s frame characteristic impedances of 50 ± 20  can be found. The common-mode termination to achieve best compliance with the test set-up will divert from the optimal impedances occurring in real vehicle applications.

III. RI TEST SET-UP The RI test set-up, according ISO 11452-2 (2004) [3] defines that the cable harness (length 1,5 ± 0,1 meter) shall be positioned at 50 mm above a metal reference plane at 0,1 meter from the front edge of the metal plated table. The RI test is specified in the frequency range 80 MHz – 18 GHz. The antenna front is at 1 meter from the cable harness (0,9 meter from the metal plated table top and the antenna center is at the harness center. The metal plated table is defined 2 meter wide and 0,9 meter height above a conductive floor.

The battery is still connected through an artificial network (AN). Also here the impedance undefined load box is defined in-between the cable harness to the DUT and the ANs. The ISO standard reads: “The load simulator box shall be placed directly on the ground plane. If the load simulator has a metallic case, this case shall be bonded to the ground

Figure 4. Simulated BCI clamp turns ratio 1:1, 2, 5; load box impedance is 150 , DUT is floating, open voltage and open loop test condition.

However, when the load box is replaced by a grounded network which represents, in total, the characteristic impedance of the cable harness, the influence of the current injection probe reduces as well as that the cable harness length related resonances and variation diminish: ≤ 3 dB, see figure 4. To enable these values in real vehicles, also the equivalent RF common-mode impedances at the ESA/ECU ports to the sensors connected have to be adapted to meet

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plane. Alternatively, the load simulator may be located adjacent to the ground plane (with the case of the load simulator bonded to the ground plane) or outside of the test chamber, provided the test harness from the DUT passes through an RF boundary bonded to the ground plane. When the load simulator is located on the ground plane, the DC power supply lines of the load simulator shall be connected through the AN(s)”. This open description allows for a very broad variety of RF impedances represented by the load box.

As result of different dimensions defined in the BCI and the RI standards, the widest metal plated table is used with a long cable harness. The cable harness is fixed at 50 mm above the metal plane and pretty undefined RF terminated by the load simulation box, which may or may not be grounded.

On the opposite side of the harness, the DUT shall be placed on an insulating support; also 50 mm height and the DUT shall be grounded by a ground strap (when defined by application).

When performing radiated immunity tests e.g. according IEC 61000-4-3, the E-field strength in front of the antenna is measured at 1 meter distance at center level, without any nearby object to the antenna. In the ISO RI case, the antenna is placed in front of the metal plated table which is at 0,9 meter distance as the distance to the cable harness has to be set to 1 meter. The E-field strength is measured 0,15 meter above the metal plate at 0,1 meter from the edge without

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Figure 5. Worst-case E-field to induced voltage ratio from a 2 meter cable harness at 50 mm above a metal reference plate while the load box/AN impedance is varied; red = 2,5 k , blue = 50  ‘sensor to GRP’ impedance.

the cable harness present. The antenna height is adjusted such that the antenna center is also at the harness cable height: 0,95 m above the ground reference plane. For each frequency, the RF generator settings e.g. forward power is recorded to obtain the field strength at that single E-field sensor position.

Due to the close proximity of the metal table, the an-

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A u t o m o t i v e RF I m m u n i t y Te s t S e t - u p A n a ly s i s : W h y Te s t R e s u lt s C a n ’ t C o m par e

the maximum induced voltage reduces when the commonmode termination resistance at one end of the harness cable topology becomes terminated close to its characteristic impedance; 150 - 200  in this case. Again this test set-up optimum common-mode termination impedance will be less in real vehicle applications.

The differences between the red and blue line results in figure 5 indicate that the worst-case resonances occurring under no-load conditions are substantially worse than when loaded with 50 , by about 10 dB. In either case, the induced voltage decreases when the load box impedance is increased. No valid simulation model has been found yet to describe these cases.

tenna’s radiation pattern is affected by mutual coupling.

More problematic w.r.t. RI test result comparison is the antenna used as the formal antenna factor and gain factor are given for an antenna in free space. When high(er) gain horn antennas are used, the distance at which a plane EM field can be expected has to be multiplied by the gain factor.

When the wavelength is 1 meter, the theoretical near-field to intermediate-field transition occurs at 1/(2) meter distance.

When the antenna gain is 12 dB e.g. with horn antennas, the distance to achieve this condition is 2 times further away as with a log-periodic antenna with a gain of 6 - 7 dB. The E-fieldstrength requirements can be met but the plane-wave conditions are not. As such, the local E-fieldstrength over the cable harness length has become antenna dependent thus unpredictable and non-calculable.

Similar to the BCI test set-up, the voltage i.e. current induced in the cable harness will depend on the RF termination at both ends of the harness. To verify this, a test set-up has been built using a horn antenna at 1 meter distance from the harness while sweeping through the frequency band from 400 MHz to 1 GHz. The antenna polarization was changed from horizontal to vertical while measuring the induced voltages in-between an insulated sensor and the reference plate. The worst case induced voltage was recorded and the load box impedance was varied between 1 and 200 , see figure 5. What was already expected is that

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IV. POSSIBLE (COR)RELATION WITH DPI OR OTHER EMC IC TEST METHODS Based on the lack of site-to-site correlation and the lack of sufficient bounds in-between the BCI set-ups, it will be very hard to find any correlation with DPI or TEM-cell results according IEC 62132-2, IEC 62132-4 or other test methods [4 - 7]. What has remained from the measurements in the 80-ies is the relation between the E-fieldstrength applied to exterior of the vehicle and the levels of the induced currents obtained on the internal harnesses of the car which appears to be 1 mA/V/m.

When with BCI a current is applied of 200 mA, which

emc Test & design guide 2011

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across 50  equals 10 Volt during calibration, this harness voltage, applied in “open loop control” will increase at resonance (worst-case) to about 200 – 300 Volt. Unfortunately, the same holds for “closed loop” BCI where due to the impedance at the sensor the local voltage may go to high extremes of > 500 Volt, as described earlier.

With the TEM cell test method as described in IEC 62132-2, only the IC itself will be exposed to EM-fields, none of the external components or the sensor front-end will be incorporated in the EM-field, unless the whole application board is applied on the 4 by 4 inch (or 100 x 100 mm) PCB structure as described in IEC 62132-1 [4].

The E-field applied will be RF voltage applied divided by distance between septum to outer enclosure, being 45 mm in a FCC TEM cell; a distance slightly less than the harness height of the BCI/RI test set-up.

When 5 Watt RF power is applied to the IC related TEM cell, terminated by 50 , the inside E-fieldstrength will become 350 V/m, which is more than enough to satisfy the 200 V/m requirements but hardly enough when all the excessive voltages occurring at resonances have to be taken into account.

From figure 5 it can be derived that the maximum induced voltage from a 2 meter harness exposed to 200 Volt/m (in the frequency range 400 – 1000 MHz) will be 20 Volt when a low impedance termination at the load box is considered. This RF signal level divided by the sensor height above the reference plane of 50 mm yields 400 Volt/m, so slightly over 5 Watt RF power should be enough to satisfy this excessive condition (under the assumption that a large broadband horn antenna will be used rather than a log-per or any other type of antenna structure suitable in that frequency range). When the cable harness exposed is characteristic terminated in common-mode at the load box side, the worst case induced voltage reduces by 8 dB (2,5 x) which means that testing with only 160 V/m is enough; quite similar to what is occurring at the BCI/ RI sensor position.

The DPI test is typically done by apinterferencetechnology.com

plying up to 30 dBm on the global pins (those port pins connected to wires leaving the PCB into a cable harness) and up to 12 dBm to the local pins (for those pins connected to local on-board components only). The coupling occurs from a 50  source in series with a coupling capacitance of max. 6,8 nF or a value which can still be handled by the circuit connected to. For the

CAN-bus interfaces, these RF voltages requirements have been raised even further to 36 dBm (4 watt; which equals 28 Volt RMS open voltage to an input or 40 Volts peak). Dedicated ESD protection structures need to be defined and special insulation techniques have to be used.

All RF voltages applied to each pin with the DPI tests are referenced to the

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testing & test equipment common Vss/ground reference layer of the PCB. As such the delta voltages appearing on the PCB application have to be known between the various pins.

V. CONCLUSIONS The present ISO standards carry many faces by their implementations; ‘open/ closed loop’, cable harness length, load box impedances, the grounding of the loading box as well as the DUT, etc., which leads to an ambiguous definition of these test set-ups, yielding severe differences in test results.

The ‘closed loop’ E-field measurement with the RI measurements close to the surface of the conductive table is incorrectly related on incident and reflective EM-field effects and therefore, together with the antenna chosen poorly correlated with EMsimulations. Also as different kind of antennas are allowed, these do yield differences in test results.

‘Open loop’ testing should be restricted to electrically ‘floating’ sensors

A u t o m o t i v e RF I m m u n i t y Te s t S e t - u p A n a ly s i s : W h y Te s t R e s u lt s C a n ’ t C o m par e

and ‘closed loop’ testing shall apply to electrically grounded applications. The use of the ‘open loop’ and ‘closed loop’ testing shall be defined in the BCI standard in relation to how the DUT will be used in its application and not be left to the interpretation of an individual EMC test engineer or specification from a car manufacturer.

As real in-vehicle applications will deviate from the artificial ISO test set-up topologies, over-testing will not guarantee immunity compliance when the ESA/ECU will be integrated into a vehicle. The equivalent ESA/ ECU RF common-mode impedance port definitions have to be aligned with the BCI/RI test set-ups or better vice versa, this to achieve comparable test data. Resonances in the test set-ups shall be avoided and equal measures shall be taken at the ESA/ECU ports also to avoid resonances while being integrated into a vehicle.

It is necessary to enforce (by standard) a unified AN (including the load

simulation box) which is encapsulated into one metal box. This box shall be grounded to the reference plane and shall yield a defined CM output impedance at the ESA/ECU port of 150 - 200  over the whole frequency range of application rather than 25  (two ANs in parallel) again in parallel to the load box input filter topology in a limited frequency band.

Care shall be taken with the real characteristic common-mode impedance occurring in a vehicle which will be around 50  and thus less that the artificial impedances one used with the test set-ups. Changing the cable harness height over the reference plane to achieve 50  could be a better alternative but will require new evidence building compared to the data gathered over the last 25 years.

The induced RF voltages occurring from the BCI can be forecasted by an analogue circuit simulator for both ‘open’ and ‘closed loop’ measurement set-ups for the various application

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conditions of the BCI clamp. When the common mode termination impedances are set to the characteristic impedance of the cable harness under these test conditions, the turns ratio of the BCI clamps becomes close to irrelevant.

The root causes for the differences in test results inbetween the BCI and RI test set-ups have been described and based on these findings the requirements for a TEM-cell or DPI test set-up can be adapted accordingly. The RF voltages induced from both the BCI and RI test set-ups could compare with the TEM cell and DPI test methods under the condition that resonances are avoided and common-mode cable harness impedance requirements are met. Fortunately, these two measures coincide in one action.

When the relations between the BCI/RI and the DPI/ TEM- cell test methods become justified, earlier compliance to the requirements can be proven which then shortens development cycles by months and probably will reduce a substantial amount of non-predictable redesigns.

ous fields and has published many papers and publications. He has been actively involved in international EMC standardization since 1988 and was awarded with the IEC 1906. He is the former project leader of the standards: IEC 61000-4-6 and IEC 61000-4-2 but has moved his focus towards EMC in integrated circuits. He was the former convenor of IEC TC47A/WG9 and until last year, a member of IEC TC47A/WG2. Coenen is CEO of EMCMCC bv. He can be reached at mart.coenen@emcmcc.nl.

Hugo Pues is senior development engineer of EMC at Melexis NV. He can be reached at hpu@melexis.com.

Thierry Bousquet is ASICs Development Engineer EMC at Continental.

He can be reached at thierry.bousquet@continental-corporation.com. n

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ACKNOWLEDGEMENT The work carried out is supported by a Dutch Governmental innovation program WBSO, under number: ZT09051042.SO

Dealing with testing issues? Interference Technology's website includes a Testing Channel focused on the latest products and developments and a Testing Forum to facilitate conversations with your colleagues. Just go to www.interferencetechnology.com/testing

REFERENCES • [1] Commission Directive 2004/104/EC of 14 October 2004 adapting to technical progress Council Directive 72/245/EEC relating to the radio interference (electromagnetic compatibility) of vehicles and amending Directive 70/156/EEC on the approximation of the laws of the Member States relating to the type-approval of motor vehicles and their trailers (followed by numerous amendments) • [2] ISO 11452-4, Road vehicles - Component test methods for electrical disturbances from narrowband radiated electromagnetic energy - Part 4: Bulk current injection (BCI) • [3] ISO 11452-2, Road vehicles - Component test methods for electrical disturbances from narrowband radiated electromagnetic energy - Part 2: Absorber-lined shielded enclosure • [4] IEC 62132-1, Integrated circuits - Measurement of electromagnetic immunity, 150 kHz to 1 GHz - Part 1: General conditions and definitions • [5] IEC 62132-2, Integrated circuits - Measurement of electromagnetic immunity - Part 2: Measurement of radiated immunity - TEM cell and wideband TEM cell method • [6] IEC 62132-3, Integrated circuits - Measurement of electromagnetic immunity, 150 kHz to 1 GHz - Part 3: Bulk current injection (BCI) method • [7] IEC 62132-4, Integrated circuits - Measurement of electromagnetic immunity 150 kHz to 1 GHz - Part 4: Direct RF power injection method • [8] Pignari S.A., Grassi F., Marliani F., Canavero F. G., "Experimental characterization of injection probes for bulk current injection," www.ursi.org/Proceedings/ProcGA05/pdf/EA.4(0494).pdf • [9] Crovetti P.S., Fiori F, "A Critical Assessment of the ClosedLoop Bulk Current Injection Immunity Test Performed in Compliance With ISO 11452-4," IEEE Transactions on Instrumentation and Measurement, April 2011.

Mart Coenen has more than 30 years of experience in EMC in variinterferencetechnology.com

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Company Name

Contact

BE

City

LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE R FC TI F CP I CA AR TI O T1 FC Ns 5& CP 18 AR T IMM 68 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/A 2L A PRO AP DU PRO CT RA SA VE DH FE TY D AZ TE RS S 03 TI N >2 G repai 00 V/ ME TE r /C R RT C A A LI B RA DO T I 160 ON SH IEL DI TE NG EF MP ES FECT IVE T NE SS

2012 emc test lab directory

2012 EMC Test Laboratory Directory

Company Name

Contact

Huntsville

EMC Compliance

(256) 650-0646

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Huntsville

NASA Marshall Space Flight Center

(256) 544-0694

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Huntsville

Redstone Technical Test Center (U.S. Army)

(256) 876-3556

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Huntsville

Wyle Laboratories

(256) 837-4411

Ft. Huachuca

EPG Blacktail Canyon Test Facility

(520) 533-5819

Phoenix

Compliance Testing, LLC, aka Flom Test Lab (480) 926-3100

Phoenix

Sypris Test & Measurement

(602) 395-5911

Scottsdale

General Dynamics C4 Systems

(480) 441-5321

Tempe

Lab-Tech, Inc.

(480) 317-0700

Tempe

National Technical Systems

(480) 966-5517

Tucson

RMS EMI Laboratory

(520) 665-5990

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Agoura

Compatible Electronics, Inc.

(818) 597-0600

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Anaheim

EMC TEMPEST Engineering

(714) 778-1726

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Brea

CKC Laboratories, Inc.

(714) 993-6112

Brea

Compatible Electronics, Inc.

(714) 579-0500

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Calabasas

National Technical Systems (NTS)

(800) 270-2516

• • • • • • • • • • • • • • • •

China Lake

NAWCWD EMI Lab

(760) 939-4669

Chino

Robinson’s Enterprise

(909) 591-3648

Costa Mesa

Independent Testing Laboratories, Inc.

BE

City

LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE R FC TI F CP I CA AR TI O T1 FC Ns 5& CP 18 AR T IMM 68 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/A 2L A PRO AP DU PRO CT RA SA VE DH FE TY D AZ TE RS S 03 TI N >2 G repai 00 V/ ME TE r /C R RT C A A LI B RA DO T I 160 ON SH IEL DI TE NG EF MP ES FECT IVE T NE SS

Common sense tells us that most engineers and designers prefer to use local testing facilities. We have created an easy-to-use directory of labs and their services grouped alphabetically by state and city, so that our readers can identify those labs closest to them. We have endeavored to make this directory as accurate as possible; however, we realize that we have not found every lab or listed every service offered. If you own or work for an EMC test lab and we have missed you or omitted one of your services, please let us know. You can add a listing or update your current listing by logging onto www.interferencetechnology.com and following the easy step-by-step instructions. You can also e-mail your additions, revisions, and suggestions to slong@interferencetechnology.com.

Alabama

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(714) 662-1011

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(310) 537-4235

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El Dorado Hills

Sanesi Associates

(916) 496-1760

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El Segundo

Wyle Laboratories

(310) 322-1763

Escondido

RF Exposure Lab, LLC

(760) 737-3131

Fremont

CKC Laboratories, Inc.

(510) 249-1170

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E. Rancho Dominguez Liberty Bel EMC/EMI Services

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emc test & design guide 2011

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Deutschland. ....................53

Lightning, Transients &ESD............................ &ESD ............................68

Filters ............................................................... ...............................................................61 Sheilded Conduits ............................................ ............................................82

France. .................................79

Shielding............................................................ ............................................................82 ............................................................

Standards ........................................................ ........................................................106

Italia.......................................99

Testing & Test Equipment...............................

Equipment...............................10

directories

España.............................. 109

Company Directory.........................................

Directory.........................................162

Polska................................. 119

Consultant Services ....................................... .......................................128 Government Directory....................................

Directory ....................................146

Nederland........................ 129

Products & Services Index...........................

Index ...........................152

Schweiz............................ 134

Standards Recap ............................................ ............................................129

Belgique............................ 141

industries & applications

Österreich....................... 145

Automotive ........................................................ ........................................................32

Professional Societies....................................

Societies ....................................138

Aerospace .................................................. 32, 72 Medical .............................................................. ..............................................................32 Military ............................................................ ............................................................124 Telecom.............................................................. ..............................................................32 .............................................................. chanGe service requested

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ITEM

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LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE R FC TI F CP I CA AR TI O T1 FC Ns 5& CP 18 AR T IMM 68 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/A 2L A PRO AP DU PRO CT RA SA VE DH FE TY D AZ TE RS S 03 TI N >2 G repai 00 V/ ME TE r /C R RT C A A LI B RA DO T I 160 ON SH IEL DI TE NG EF MP ES FECT IVE T NE SS

2012 emc test lab directory

Company Name

Contact

Fremont

Compliance Certification Services

(510) 771-1000

Fremont

Elliott Laboratories

(408) 245-7800

Fremont

Elma Electronics, Inc.

(510) 656-3400

Fremont

EMCE Engineering, Inc.

(510) 490-4307

• • •

Fullerton

DNB Engineering, Inc.

(800) 282-1462

Fullerton

National Technical Systems (NTS)

(714) 879-6110

Gardena

Parker EMC Engineering

(910) 823-2345

Garden Grove

Semtronics

(714) 799-9810

Gilroy

Scientific Hardware Systems

(408) 848-8868

Irvine

7Layers, Inc.

+10949 7166512

•

Irvine

Mitsubishi Digital Electronics America Inc.

(949) 465-6206

•

Irvine

Northwest EMC

(888) 364-2378

Lake Forest

Compatible Electronics, Inc.

(949) 587-0400

Lake Forest

Intertek Testing Services

(949) 448-4100

Los Angeles

Field Management Services

(323) 937-1562

•

Los Gatos

Pulver Laboratories, Inc.

(408) 399-7000

•

Mariposa

CKC Laboratories, Inc.

(209) 966-5240

Menlo Park

Intertek Testing Services

(650) 463-2900

Milpitas

CETECOM, Inc.

(408) 586-6200

Mountian View

Electro Magnetic Test, Inc.

(650) 965-4000

Mountain View

EMT Labs

(650) 965-4000

Mountain View

EMC Compliance Management Group

(650) 988-0900

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Newark

Elliott Laboratories

(510) 578-3500

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North Highlands Northrop Grumman ESL

(916) 570-4340

Oakland

ITW Richmond Technology

(510) 655-1263

•

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Orange

G & M Compliance, Inc.

(714) 628-1020

Pico Rivera

Stork Garwood Laboratories, Inc.

(562) 949-2727

• • • • • • • •

Pleasanton

MiCOM Labs

(925) 462-0304

•

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Pleasanton

TÜV Rheinland of North America

(925) 249-91923

• •

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Poway

APW Electronic Solutions

•

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(858) 679-4550

•

Rancho St. Margarita Aegis Labs, Inc.

(949) 454-8295

• •

Redondo Beach

Northrop Grumman Space Tech. Sector

(310) 812-3162

• • •

Riverside

DNB Engineering, Inc.

(800) 282-1462

•

•

Riverside

Global Testing

(951) 781-4540

• • •

Sacramento

Northrop-Grumman EM Systems Lab

(916) 570-4340

•

San Clemente

Stork Garwood Laboratories, Inc.

(949) 361-9189

• • •

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San Diego

Lambda Electronics

(619) 575-4400

•

•

San Diego

NEMKO

(858) 755-5525

• • • • • • • • • • • • • • • •

• •

San Diego

TÜV SÜD America, Inc.

(858) 678-1400

•

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• •

•

Santa Clara

Montrose Compliance Services, Inc.

(408) 247-5715

•

•

San Jose

Arc Technical Resources, Inc.

(408) 263-6486

• • • • • • • •

San Jose

ATLAS Compliance & Engineering, Inc.

(866) 573-9742

• • •

San Jose

Safety Engineering Laboratory

(408) 544-1890

San Jose

Underwriters Laboratories, Inc.

(408) 754-6500

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Company Name

LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE RT FC IFIC CP AT AR IO N T1 FC s 5& CP 18 AR T6 IMM 8 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/ PRO A 2L A AP DU PRO CT RA SA VE DH FE TY D AZ TE RS ST 03 ING >2 repai 00 V/ ME TE r /C R RT C A A LI B RA DO TI O -16 SH N 0 IEL DI TE NG EF MP F EC ES TIV T EN ES S

City

& canada

Contact

BE

u n i t e d s tat e s

San Ramon

Electro-Test, Inc.

(925) 485-3400

• •

Santa Clara

MET Laboratories, Inc.

(408) 748-3585

• • •

• • • • • •

Santa Clara

Montrose Compliance Services, Inc.

(408) 247-5715

Sunnyvale

Bay Area Compliance Labs.

(408) 732-9162

• • • • • • • • •

• •

Sunnyvale

Elliott Laboratories, Inc.

(408) 245-7800

• • •

• •

Sunnyvale

Sypris Test & Measurement

(408) 720-0006

Sunol

ITC Engineering Services, Inc.

(925) 862-2944

Torrance

Lyncole XIT Grounding

(310) 214-4000

Trabuco Canyon

RFI International

(949) 888-1607

Union City

MET Laboratories, Inc.

(510) 489-6300

Van Nuys

Sypris Test & Measurement

(818) 830-9111

Boulder

Ball Aerospace & Technology Corp.

(303) 939-4618

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Boulder

Percept Technology Labs, Inc.

(303) 444-7480

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Boulder

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Colorado •

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Intertek Testing Services

(303) 786-7999

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Colorado Springs INTERTest Systems, Inc.

(719) 522-1402

• •

Lakewood

Electro Magnetic Applications, Inc.

(303) 980-0070

•

•

Littleton

Sypris Test & Measurement

(303) 798-2243

•

Longmont

EMC Integrity, Inc.

(888) 423-6275

Rollinsville

Criterion Technology

(303) 258-0100

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Connecticut East Haddam

Global Certification Laboratories, Ltd.

(860) 873-1451

East Haddam

Turnkey OATS Construction, LLC

(860) 873-8975

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Middletown

Product Safety International

(860) 344-1651

Milford

Harriman Associates

(203) 878-3135

•

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Newtown

TÜV Rheinland of North America, Inc.

(203) 426-0888

Norwalk

Panashield, Inc.

(203) 866-5888

Stratford

Total Shielding Systems

(203) 377-0394

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District of Columbia Washington

American European Services, Inc.

(202) 337-3214

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Boca Raton

Advanced Compliance Solutions, Inc.

(561) 961-5585

•

Boca Raton

Jaro Components

(561) 241-6700

Cocoa Beach

Elite Electronic Engineering Company

(800) ELITE-11

Dade City

Product Safety Engineering, Inc.

(352) 588-2209

•

Dade City

TÜV SÜD America, Inc.

(352) 588-1033

•

• • • • •

Jupiter

East West Technology Corporation

(561) 776-7339

• •

Lake Mary

Test Equipment Connection

(800) 615-8378

Largo

Walshire Labs, LLC

(727) 530-8637

Melbourne

Rubicom Systems, Division of ACS

(321) 951-1710

Newberry

Timco Engineering, Inc.

(888) 472-2424

Orlando

Sypris Test & Measurement

(800) 839-4959

Orlando

Qualtest, Inc.

(407) 313-4230

• • •

Palm Bay

Harris Corporation EMI/TEMPEST Lab

(321) 727-6209

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Florida

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FL

Company Name

Contact

Alpharetta

EMC Testing Laboratories, Inc.

(770) 475-8819

• • • • • • •

Alpharetta

U.S. Technologies, Inc.

(770) 740-0717

•

Buford (Atlanta)

Advanced Compliance Solutions, Inc.

(770) 831-8048

Lawrenceville

Motorola Product Testing Services

(770) 338-3795

•

Peachtree

Panasonic Automotive

(770) 515-1443

•

Acme Testing Company

(360) 595-2785

Addison

Sypris Test & Measurement

(630) 620-5800

Downers Grove

Elite Electronic Engineering, Inc.

(630) 495-9770

Montgomery

E.F. Electronics Co.

(630) 897-1950

Mundelein

Midwest EMI Associates, Inc.

Northbrook

Underwriters Laboratories, Inc.

Palatine

BE

City

LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE R FC TI F CP I CA AR TI O T1 FC Ns 5& CP 18 AR T IMM 68 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/A 2L A PRO AP DU PRO CT RA SA VE DH FE TY D AZ TE RS S 03 TI N >2 G repai 00 V/ ME TE r /C R RT C A A LI B RA DO T I 160 ON SH IEL DI TE NG EF MP ES FECT IVE T NE SS

2012 emc test lab directory

Georgia •

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idaho Plummer

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Illinois •

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(847) 918-9886

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(847) 272-8800

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Trace Laboratories–EMC

(847) 934-5300

•

• • • • •

• •

Peoria

EMC Testing Inc., A Caterpillar Company

(309) 578-1213

•

•

Poplar Grove

LF Research EMC Design & Test Facility

(815) 566-5655

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• • • •

Rockford

National Technical Systems (NTS)

(815) 315-9250

Rockford

Ingenium Testing, LLC

(815) 315-9250

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Romeoville

Radiometrics Midwest Corp.

(815) 293-0772

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Wheeling

D.L.S. Electronic Systems, Inc.

(847) 537-6400

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Woodridge

Zero Ground LLC

(866) ZERO-GND

Crane

Naval Surface Warfare Ctr., Crane Div.

(812) 854-5107

•

Fort Wayne

Raytheon

(260) 429-4335

• •

Indianapolis

Raytheon Technical Services Co., EMI Lab

(317) 306-8471

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Kokomo

Delphi Delco Electronic Systems

(765) 451-5011

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Kimballton

Liberty Labs, Inc.

(712) 773-2199

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Elk Horn

World Cal, Inc.

(712) 764-2197

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Rogers Labs, Inc.

(913) 837-3214

Lexington

Lexmark International EMC Lab

(606) 232-7650

Lexington

Intertek Testing Services

(859) 226-1000

Lexington

dBi Corporation

(859) 253-1178

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Maryland Annapolis

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Northrop Grumman Space & Mission Systems (410) 266-1700

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emc test & design guide 2011

Company Name

LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE RT FC IFIC CP AT AR IO N T1 FC s 5& CP 18 AR T6 IMM 8 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/ PRO A 2L A AP DU PRO CT RA SA VE DH FE TY D AZ TE RS ST 03 ING >2 repai 00 V/ ME TE r /C R RT C A A LI B RA DO TI O -16 SH N 0 IEL DI TE NG EF MP F EC ES TIV T EN ES S

City

& canada

Contact

BE

u n i t e d s tat e s

Baltimore

MET Laboratories, Inc.

(410) 354-3300

Beltsville

Antenna Research Associates

(301) 937-8888

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Columbia

DRS Advanced Programs

(410) 312-5800

Columbia

PCTest Engineering Lab

(410) 290-6652

Damascus

F-Squared Laboratories

(301) 253-4500

Elkridge

ATEC Industries, Ltd.

(443) 459-5080

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•

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• • • •

Frederick

The American Association for

Laboratory Accreditation (A2LA)

(301) 644-3217

Gaithersburg

Washington Laboratories, Ltd.

(301) 216-1500

•

Hunt Valley

Trace Laboratories–East

(410) 584-9099

•

Patuxent River

Naval Air Warfare Ctr., Aircraft Div.

(301) 342-1663

Rockville

P.J. Mondin, P.E. Consultants

(301) 460-5864

Rockville

Spectrum Research & Testing Laboratory, Inc.

(301) 670-2818

Salisbury

Filter Networks

(410) 341-4200

Westminster

Electrical Test Instruments, Inc.

(410) 857-1880

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Consultant Services

Braco Compliance Limited A-Tick, C-Tick and Telepermit local agent for Australia and New Zealand.

Bruce Maule Braco Compliance Limited.

PO Box 31188, ILAM, Christchurch 8444, NZ +64 21 208 4303 • enquiries@bracocompliance.com www.bracocompliance.com

628 LeVander Way S. St. Paul, MN 55075

interferencetechnology.com

Braco_BC ad.indd 1

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MA

Company Name

Contact

BE

City

LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE R FC TI F CP I CA AR TI O T1 FC Ns 5& CP 18 AR T IMM 68 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/A 2L A PRO AP DU PRO CT RA SA VE DH FE TY D AZ TE RS S 03 TI N >2 G repai 00 V/ ME TE r /C R RT C A A LI B RA DO T I 160 ON SH IEL DI TE NG EF MP ES FECT IVE T NE SS

2012 emc test lab directory

Massachusetts Billerica

Quest Engineering Solutions

(978) 667-7000

Billerica

Sypris Test & Measurement

(978) 663-2137

• •

•

Boxborough

Intertek Testing Services

(978) 263-2662

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Boxborough

National Technical Systems (NTS)

(978) 266-1001

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Foxboro

N.E. Product Safety Society, Inc.

(508) 543-6599

Gloucester

Euroconsult, Inc.

(978) 282-8890

Lexington

Design Automation, Inc.

(781) 862-8998

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Littleton

Curtis-Straus LLC, subsidiary of Bureau Veritas (978) 486-8880

• • •

Littleton

Intertek Testing Services

(978) 486-0432

Mansfield

Motorola Test Lab Services Group

(508) 851-8484

Marlboro

IQS, Div. of The Compliance Management Group (508) 460-1400

Marlboro

The Compliance Management Group

(508) 281-5985

Milford

Test Site Services, Inc.

(508) 634-3444

• • •

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Newton

EMC Test Design, LLC

(508) 292-1833

Peabody

TUV SUD America Inc.

(800) TUV-0123

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Pittsfield

Lightning Technologies, Inc.

(413) 499-2135

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Wilmington

Thermo Fisher Scientific

(978) 275-0800

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Woburn

Chomerics, Div. of Parker Hannifin Corp. (781) 935-4850

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• •

Woburn

NELCO

(781) 933-1940

•

TÜV SÜD America, Inc.

(248) 393-6984

•

Michigan Auburn Hills Belleville

Willow Run Test Labs, LLC

(734) 252 9785

•

•

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Burton

Trialon Corporation

(810) 341-7931

•

•

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•

Detroit

National Technical Systems

(313) 835-0044

Grand Rapids

Intertek Testing Services

(800) WORLDLAB •

Holland

TÜV SÜD America, Inc.

(616) 546-3902

Milford

Jacobs Technology, Inc.

(248) 676-1101

•

• •

•

Novi

Sypris Test & Measurement

(248) 305-5200

Novi

Underwriters Laboratories, Inc.

(248) 427-5300

•

• •

•

Plymouth

TÜV SÜD America, Inc.

(734) 455-4841

•

Saginaw

Delphi Steering EMC Lab

(989) 797-0318

Sister Lakes

AHD EMC Lab

(269) 313-2433

Warren

Detroit Testing Laboratory, Inc.

(586) 754-9000

(888) 364-2378

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Minnesota Brooklyn Park

32

Northwest EMC, Inc.

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•

emc test & design guide 2011

Company Name

LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE RT FC IFIC CP AT AR IO N T1 FC s 5& CP 18 AR T6 IMM 8 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/ PRO A 2L A AP DU PRO CT RA SA VE DH FE TY D AZ TE RS ST 03 ING >2 repai 00 V/ ME TE r /C R RT C A A LI B RA DO TI O -16 SH N 0 IEL DI TE NG EF MP F EC ES TIV T EN ES S

City

& canada

Contact

BE

u n i t e d s tat e s

Glencoe

International Certification Services, Inc.

(320) 864-4444

•

Maple Grove

TUV Rheinland of North America, Inc.

(763) 315-5012

•

Millville

TÜV SÜD America, Inc.

(507) 798-2483

• •

Minneapolis

Alpha EMC, Inc.

(763) 561-4410

• •

• •

Minneapolis

Environ Laboratories, LLC

(800) 826-3710

•

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Minneapolis

Honeywell

(612) 951-5773

New Brighton

TÜV SÜD America, Inc.

(651) 631-2487

•

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New Hope

Conductive Containers, Inc.

(763) 537-2090

Oakdale

Intertek Testing Services

(651) 730-1188

• •

Rochester

IBM

(507) 253-6201

•

St. Paul

3M

(651) 778-4577

• •

Taylor Falls

TÜV SÜD America, Inc.

(651) 638-0297

•

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• • •

• • • •

Boeing-St. Louis EMC Lab

(314) 233-7798

•

NCEE Labs

(402) 472-5880

•

PolyPhaser Corp.

(775) 782-2511

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• • •

Missouri St. Louis

• •

•

•

• • •

•

Nebraska Lincoln

• • •

Nevada Minden

•

•

New Hampshire

Goffstown

Retlif Testing Laboratories

(603) 497-4600

• • • • • • • • •

• • • • •

Hudson

Core Compliance Testing Services

(603) 889-5545

•

•

•

• •

•

Sandown

Compliance Worldwide, Inc.

(603) 887-3903

•

•

• • • •

•

•

•

• •

New Jersey Annandale

NU Laboratories, Inc.

(908) 713-9300

•

•

•

Bridgeport

Analab, LLC

(800) analab-X

•

•

•

•

Bridgewater

Lichtig EMC Consulting

(908) 541-0213

•

Camden

L-3 Communication Systems-East

(856) 338-3000

Clifton

NJ-MET

(973) 546-5393

•

•

Edison

Metex Corporation

(732) 287-0800

•

Edison

TESEQ, Inc.

(732) 417-0501

•

Fairfield

SGS U.S. Testing Co., Inc.

(800) 777-8378

•

•

•

• •

Farmingdale

EMC Technologists, A Div. of I2R Corp.

(732) 919-1100

•

•

• • • • •

•

Hillsborough

Advanced Compliance Laboratory, Inc.

(908) 927-9288

•

Holmdel

Global Products Compliance Laboratory

(732) 332-6000

•

• • •

•

Lakehurst

Naval Air Warfare Ctr., Aircraft Div.

(732) 323-2085

Lakewood

BAE Systems

(732) 364-0049

• • •

•

• •

• •

•

Lincroft

Don HEIRMAN Consultants

(732) 741-7723

•

•

Piscataway

Telcordia Technologies, Inc.

(800) 521-2673

• • •

•

•

• •

• •

Rutherford

SGS International Certification Services, Inc. (800) 747-9047

•

Sayreville

Sypris Test & Measurement

•

interferencetechnology.com

(732) 721-6116

•

• • • •

• •

•

• •

•

interference technology

•

•

33

City

Company Name

Contact

BE

NY

LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE R FC TI F CP I CA AR TI O T1 FC Ns 5& CP 18 AR T IMM 68 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/A 2L A PRO AP DU PRO CT RA SA VE DH FE TY D AZ TE RS S 03 TI N >2 G repai 00 V/ ME TE r /C R RT C A A LI B RA DO T I 160 ON SH IEL DI TE NG EF MP ES FECT IVE T NE SS

2012 emc test lab directory

Thorofare

NDI Engineering Company

(856) 848-0033

Tinton Falls

National Technical Systems (NTS)

(732) 936-0800

• • • •

Wayne

Sypris Test & Measurement

(973) 628-1363

•

• • •

•

•

• • • • • • • • • •

• •

•

• •

•

•

•

•

• •

•

New Mexico Albuquerque

Advanced Testing Services, Inc.

(505) 292-2032

White Sands

USA WSMR, Survivability Directorate

(575) 678-6107

• • •

• •

New York Bohemia

Dayton T. Brown, Inc.

(800) TEST-456

• • • • • • • •

• • •

College Point

Aero Nav Laboratories, Inc.

(718) 939-4422

•

•

•

• •

• •

•

• •

Deer Park

MCG Surge Protection, Inc.

(800) 851-1508

•

Deer Park

Universal Shielding Corp.

(631) 667-7900

•

Groton

Diversified T.E.S.T. Technologies

(607) 898-4218

•

• • •

•

• • •

•

Groton

Source 1 Compliance

(315) 730-5667

•

• • •

•

• • •

•

Johnson City

BAE Systems Controls, Inc.

(607) 770-3771

• •

•

• •

•

Johnstown

Electro-Metrics Corp.

(518) 762-2600

•

Liverpool

Diversified Technologies

(315) 457-0245

•

• • •

•

• • •

•

Liverpool

Source1 Solutions

(315) 730-5667

•

• • •

•

• • •

•

Medford

American Environments Co.

(631) 736-5883

•

• • • • •

• •

•

•

• •

Medina

TREK, Inc.

(585) 798-3140

•

• • • •

•

• • • • •

• •

•

Melville

Underwriters Laboratories, Inc.

(631) 271-6200

•

•

Northport

Mohr, R.J., Assoc., Inc.

(631) 754-1142

Owego

Lockheed Martin Federal Systems

(607) 751-2938

• • •

Palmyra

Source1 Solutions

(315) 730-5667

•

Poughkeepsie

IBM Corp. Poughkeepsie EMC Lab

(607) 752-2225

•

Rochester

Chomerics, Div. of Parker Hannifin

(781) 939-4158

Rochester

Spec-Hardened Systems

(585) 225-2857

• • • • •

Rochester

TÜV Rheinland of North America

(585) 426-5555

• •

Retlif Testing Laboratories

(631) 737-1500

• • • • • • • • •

• • • • •

• •

•

• • • • • •

•

• • •

•

•

•

•

•

•

•

•

•

•

• •

• •

•

•

•

• • •

• • •

•

•

• •

Ronkonkoma

North Carolina Cary

CertifiGroup

(800) 422-1651

Cary

MET Laboratories, Inc.

(919) 481-9319

• • •

Fayetteville

Partnership for Defense Innovation R&D Lab (910) 307-3000

•

•

•

Greensboro

Electrical South, LP

(800) 950-9550

Greenville

Lawrence Behr Associates (LBA)

(252) 757-0279

•

New Bern

iNARTE, Inc.

(252) 672-0111

•

Raleigh

MicroCraft Corporation

• • •

•

• • • • • •

(919) 872-2272

Res. Triangle Pk. Educated Design & Dev., Inc. (ED&D)

(919) 469-9434

•

Res. Triangle Pk. IBM RTP EMC Test Labs

(919) 543-0837

Res. Triangle Pk.

Underwriters Laboratories, Inc.

(919) 549-1400

Youngsville

Flextronics International EMC Labs

(919) 554-0901

• • • • • • • • • •

Youngsville

TÜV Rheinland Of North America

(919) 554-3668

34

interference technology

• •

• • •

•

• •

•

•

• •

•

• •

• • •

•

• •

•

•

•

•

•

•

• • • • •

• •

•

• •

•

• •

• •

• • •

•

emc test & design guide 2011

Company Name

LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE RT FC IFIC CP AT AR IO N T1 FC s 5& CP 18 AR T6 IMM 8 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/ PRO A 2L A AP DU PRO CT RA SA VE DH FE TY D AZ TE RS ST 03 ING >2 repai 00 V/ ME TE r /C R RT C A A LI B RA DO TI O -16 SH N 0 IEL DI TE NG EF MP F EC ES TIV T EN ES S

City

& canada

Contact

BE

u n i t e d s tat e s

Ohio Brooklyn Heights Sypris Test & Measurement

(216) 741-7040

•

Burton

(877) 405-1580

• • • • • • • • •

•

•

F-Squared Laboratories, Inc.

Chesterland

EU Compliance Services, Inc.

(440) 918-1425

•

• • •

•

• •

Cleveland

CSA International

(216) 524-4990

•

•

Cleveland

NASA GRC EMI Lab

(216) 433-2533

•

•

Cleveland

Smith Electronics

(440) 526-4386

•

•

Fairborn

Sypris Test & Measurement

(937) 427-3444

•

Mason

L-3 Cincinnati Electronics

(513) 573-6100

•

•

•

•

•

•

Mentor

EU Compliance Services, Inc.

(440) 918-1425

•

• •

•

•

•

Springboro

Pioneer Automotive Technologies

(937) 746-6600

•

•

•

•

• •

Integrated Sciences, Inc.

(918) 493-3399

•

Beaverton

Tektronix

(407) 551-2738

•

•

•

Hillsboro

Cascade TEK

(503) 648-1818

•

•

•

Hillsboro

ElectroMagnetic Investigations, LLC

(503) 466-1160

•

• • •

•

• •

Portland

Northwest EMC, Inc.

(888) 364-2378

• •

•

•

• •

• • •

Oklahoma Tulsa

Oregon

interferencetechnology.com

•

•

•

interference technology

35

WA

Company Name

Contact

BE

City

LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE R FC TI F CP I CA AR TI O T1 FC Ns 5& CP 18 AR T IMM 68 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/A 2L A PRO AP DU PRO CT RA SA VE DH FE TY D AZ TE RS S 03 TI N >2 G repai 00 V/ ME TE r /C R RT C A A LI B RA DO T I 160 ON SH IEL DI TE NG EF MP ES FECT IVE T NE SS

2012 emc test lab directory

Portland

TÜV SÜD America, Inc.

(503) 598-7580

•

Tillamook

ElectroMagnetic Investigations, LLC

(503) 466-1160

•

•

•

•

Pennsylvania Annville

CHAR Services, Inc.

(717) 867-2788

• •

•

Boalsburg

Seven Mountains Scientific, Inc.

(814) 466-6559

•

•

•

Glenside

Electro-Tech Systems, Inc.

(215) 887-2196

•

•

•

Harleysville

Retlif Testing Laboratories

(215) 256-4133

• • • • • • • • •

Hatfield

Laboratory Testing, Inc.

(800) 219-9095

New Castle

Keystone Compliance LLC

(724) 657-9940

• • • • •

Norristown

LCR Electronics, Inc.

(610) 278-0840

•

Pottstown

BEC Inc.

(610) 970-6880

•

• • •

•

State College

Videon Central, Inc.

• • •

• • • • •

• •

•

•

•

•

• • •

• • • •

•

•

• •

•

•

(814) 235-1111

•

W. Conshohocken Alion Science & Technology

(610) 825-1960

• • •

• •

•

• •

• •

Willow Grove

Nelson Design Services

(215) 784-9600

Knoxville

Global Testing Labs LLC

(865) 525-0137

•

Knoxville

Southern Testing Services, Inc.

(865) 966-5330

Austin

Austin EMC

(512) 219-6650

•

Austin

BAE Systems IDS Test Services

(512) 929-2410

Austin

MET Laboratories, Inc.

(512) 287-2500

• • •

Cedar Park

TDK RF Solutions, Inc.

(512) 258-9478

•

Euless

Ronald G. Jones, P.E.

(817) 267-1476

•

Houston

DNV Certification

(281) 721-6600

•

Lewisville

Nemko USA

(972) 436-9600

• •

• • • • •

Plano

National Technical Systems (NTS)

(972) 509-2566

• • • • • • • • • •

• •

•

• •

Plano

Intertek Testing Services

(972) 202-8800

• • • • •

•

• •

Richardson

Sypris Test & Measurement

(972) 231-4443

•

Round Rock

Professional Testing (EMI), Inc.

(512) 244-3371

•

• • •

• • •

San Antonio

Southwest Research Institute

(210) 684-5111

•

Coalville

DNB Engineering, Inc.

(435) 336-4433

•

•

Ogden

Little Mountain Test Facility (LMTF)

(801) 315-2320

• • •

Salt Lake City

Communication Certification Laboratory

(801) 972-6146

•

• • • • •

• • •

Salt Lake City

L3 Communication Systems–West

(801) 594-2560

•

• •

•

•

Essex Junction

Huber & Suhner

(802) 878-0555

•

•

Middlebury

Green Mountain Electromagnetics, Inc.

(802) 388-3390

• • •

• •

•

•

•

•

•

•

•

•

•

•

•

•

• • • • • •

• • •

•

• •

• • • • •

•

•

• • • • •

Tennessee

Texas

•

•

• •

• • • • • • • • • • • •

•

• •

• •

Utah

• • • • •

• •

•

•

• •

Vermont

36

interference technology

emc test & design guide 2011

Company Name

Contact

Falls Church

Raytheon Prototype Services

(703) 849-1562

•

Fredericksburg

Vitatech Engineering, LLC

(540) 286-1984

•

•

• • •

• • •

BE

City

& canada LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE RT FC IFIC CP AT AR IO N T1 FC s 5& CP 18 AR T6 IMM 8 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/ PRO A 2L A AP DU PRO CT RA SA VE DH FE TY D AZ TE RS ST 03 ING >2 repai 00 V/ ME TE r /C R RT C A A LI B RA DO TI O -16 SH N 0 IEL DI TE NG EF MP F EC ES TIV T EN ES S

u n i t e d s tat e s

Virginia Herndon

Rhein Tech Laboratories, Inc.

(703) 689-0368

•

McLean

American TCB

(703) 847-4700

• •

Reston

TEMPEST, Inc. (VA)

(703) 709-9543

•

Richmond

Technology International, Inc.

(804) 794-4144

• •

• •

• •

•

• •

•

• • •

• •

• •

•

• • • • •

• •

• •

• •

•

•

•

• • •

•

• •

Washington Acme

Acme Testing Company

(360) 595-2785

• • •

Bothell

CKC Laboratories, Inc

(425) 402-1717

• • • •

•

• •

• • •

•

• •

Sultan

Northwest EMC, Inc.

(888) 364-2378

•

•

•

•

• •

Butler

Emission Control, Ltd.

(262) 790-0092

•

Cedarburg

L.S. Research

(262) 375-4400

• •

•

•

•

•

Genoa City

D.L.S. Electronic Systems, Inc.

(847) 537-6400

• •

•

•

Milwaukee

Curtis Industries/Filter Networks

(414) 649-4200

•

•

Neenah

International Compliance Laboratories

(920) 720-5555

• • • • •

•

•

Wisconsin

•

Canada Alberta

Airdrie

Electronics Test Centre - Airdrie

(403) 912-0037

•

• • •

•

• •

• •

Calgary

EMSCAN Corporation

(403) 291 0313

•

•

Calgary

National Technical Systems (NTS)

(403) 568-6605

• • • • • • • • • • • • • •

•

• •

Medley

Aerospace Engrg. Test Establishment (DND) (780) 840-8000

•

•

• • • • •

•

British Columbia Abbotsford

Protocol EMC

(604) 218-1762

• • •

• •

Kelowna

Celltech Labs, Inc.

(250) 765-7650

• •

• • • • •

• •

•

Pitt Meadows

Tranzeo EMC Labs Inc.

(604) 460-4453

•

• • •

•

Richmond

LabTest Certification, Inc.

(604) 247-0444

• • • • • • •

• • •

•

Ontario

Kanata

Electronics Test Centre

(613) 599-6800

•

• • • • • • • •

Merrickville

EMC Consulting, Inc.

(613) 269-4247

• • • • •

• • • •

Missisauga

Intertek ETL Semko

(905) 678-7820

•

•

•

•

Nepean

APREL Laboratories

(613) 820-2730

•

• •

Nepean

Multilek Inc.

(613) 226-2365

•

Oakville

Ultratech Group of Labs

(905) 829-1570

•

• • • • •

•

Ottawa

ASR Technologies

(613) 737-2026

• • • •

• • •

interferencetechnology.com

• • • • •

•

•

• • • • •

• •

• • • •

•

•

• • • • •

•

• •

• •

•

interference technology

37

City

Company Name

Contact

BE

LLC OR E Cb /cab / TEL COR / TC EM DI A B ISS IO N EM S P/L IG H TN ES ING D EF FE eu CT ro S CE R FC TI F CP I CA AR TI O T1 FC Ns 5& CP 18 AR T IMM 68 UN LI G I T Y HT NI N GS MIL TR - ST IKE D1 MIL 8 8/ 125 - ST D4 61/ NV 4 62 LA P/A 2L A PRO AP DU PRO CT RA SA VE DH FE TY D AZ TE RS S 03 TI N >2 G repai 00 V/ ME TE r /C R RT C A A LI B RA DO T I 160 ON SH IEL DI TE NG EF MP ES FECT IVE T NE SS

2012 emc test lab directory

Ottawa

Nemko

(613) 737-9680

• • • • • • • • • • • • • • • • • • • •

Ottawa

Power & Controls Engineering Ltd.

(613) 829-0820

•

• •

•

•

Ottawa

Raymond EMC Enclosures Limited

(800) EMC-1495

• •

Scarborough

Vican Electronics

(416) 412-2111

•

• • • • •

•

•

•

Toronto

CSA International

(866) 797-4272

• •

• •

Toronto

Global EMC Inc.

(905) 883-8189

• •

• •

• •

•

• •

• • • • •

•

Quebec Montreal

Centre de Recherche Industrielle du Quebec (514) 383-1550

•

• •

•

•

Quebec

Comlab, Inc.

(418) 682-3380

• • •

•

Quebec

FISO Technologies

(418) 688-8065

•

•

•

• •

•

ASIA

EUROPE

CHINA

AUSTRIA

Beijing

Teseq Company Limited

+86 10 8460 8080

Seibersdorf

Shanghai

KIKUSUI Trading (Shanghai) Co., Ltd

43 (0) 50550 2805

Shanghai

CETECOM Shanghai

+86 (0) 21 6879 5890

DENMARK

Shenzhen

MET Laboratories Inc.

+86 755 82911867

Horsholm

Kowloon

Intertek China

(852) 2 173 8810

Kowloon

Chomerics Asia Pacific

(852) 2 428 8008

ISRAEL 972-8-9797799

JAPAN Watari

Cosmos Corporation

81 (0)598-60-1827

Chiba

EMC Kashima Corporation

81 478-82-0963

Tokyo

CETECOM Japan

+81 (0) 3 6663 8990

Tokyo

Technology International

81 (0)3 5793 1558

KOREA Gyeonggi-do CETECOM MOVON Ltd, Korea

+82-(0)31-321-2988

Seoul

82 (0) 2 2026 0191

MET Laboratories, Inc.

TAIWAN New Taipei City MET Laboratories, Inc.

+886 2 8227 8887

Taipei City

+886 2 2564 3338

38

CETECOM Taiwan

interference technology

Austrian Research Centers

Delta

43 (0) 50550 2805

+45 72 19 49 99

Blomberg

Phoenix Testlab GmbH

+49 5235 9500 0

Dortmund

EMC Test NRW GmbH

+49 231 97 42-750

Egling

MOOSER Consulting GmbH

+49 8176 92250

Erlangen

Siemens AG

Essen

CETECOM GmbH (Germany)

+49 20 54 95 19 0

Karlsruhe

Siemens AG

+49 721 595-2039

Services: Emissions, EMP/Lighting Effects, ESD, Euro Certifications, Immunity, MIL-STD 461/462, Product Safety

Ludwigsburg

Mooser EMC Technik GmbH

Israel Testing Laboratories

GERMANY

HONG KONG

Lod

Services: Emissions, EMP, Lighting Effects, Immunity, MIL-STD 188/125, MIL-STD 461/462, Shielding Effectiveness, Tempest

+49 9131 7-32977

Services: Emissions/ ESD/ Immunity

+49 7141 648260

Services: Emissions, ESD, Euro Certifications, Immunity, MIL-STD 461/462, RS03>200 V/meter

Moggast

EMCCons Dr. Rasek GmbH & Co

Services: BELLCORE/TELCORDIA, CB/CAB/TCB, EMISSIONS, EMP/ LIGHTNING EFFECTS, ESD, EURO CERTIFICATIONS, FCC PART 15 & 18, FCC PART 68, IMMUNITY, LIGHTNING STRIKE, MIL-STD 188/125, MIL-STD 461/462, NVLAP/A2LA APPROVED, PRODUCT SAFETY, RADHAZ TESTING, RS03 > 200 V/METER, REPAIR/CALIBRATION, RTCA DO-160, SHIELDING EFFECTIVENESS

Munich

National Technical Systems (NTS)

+49 9194 9016

+49 89 787475 160

Neckartenzlingen Hirschmann Car Communication GmbH

+49 7127 14 1437

Ratingen

7Layers

+49 210 27490

Services: Emissions, EMP, Lighting Effects, ESD, Euro Certifications, FCC Part 15 & 18, Immunity, Lightning Strike, MIL-STD 461/462, Shielding Effectiveness, Tempest

emc test & design guide 2011

u n i t e d s tat e s

& canada

Saarbruecken CETECOM GmbH

+49 681 598 8438

Eindhoven

EMCMCC

+ 49 271 382702

Services: Emissions, ESD, Euro Certifications, Immunity, MIL-STD 461/462, RS03>200 V/meter

Eindhoven

Philips Innovation Services

Services: Emissions, ESD, Immunity

Eindhoven

Philips Applied Technologies EMC

31 40 27 44316

Woerden

D.A.R.E.!! Consultancy

31 348 430 979

Woerden

D.A.R.E.!! Instruments

31 348 430 979

Siegen

EMC Testhaus Dr. Schreiber GmbH

Services: Emissions, EMP, Lighting Effects, ESD, Euro Certifications, Immunity, Lightning Strike, MIL-STD 461/462, Product Safety, Repair/Calibration, RTCA DO-160, Shielding Effectiveness

Straubing

EMV Testhaus GmbH

+49 9421 56868-0

Straubing

TÜV SÜD SENTON GmbH

+49 9421 5522 0

Services: Emissions, ESD, Euro Certifications, FCC Part 15 & 18,

Immunity, MIL-STD 461/462, RTCA DO-160

Unterleinleiter EMCCons Dr. Rasek GmbH & Co

+31-6-53811267

+31-40-2746762

UNITED KINGDOM

+49 9194 9016

Services: BELLCORE/TELCORDIA, CB/CAB/TCB, EMISSIONS, EMP/ LIGHTNING EFFECTS, ESD, EURO CERTIFICATIONS, FCC PART 15 & 18, FCC PART 68, IMMUNITY, LIGHTNING STRIKE, MIL-STD 188/125, MIL-STD 461/462, NVLAP/A2LA APPROVED, PRODUCT SAFETY, RADHAZ TESTING, RS03 > 200 V/METER, REPAIR/CALIBRATION, RTCA DO-160, SHIELDING EFFECTIVENESS

Aylesbury

3C Test Ltd

+44 (0) 1327 857500

Basingstoke

RFI Global Services Ltd. (UL)

+44 (0) 1256 31 2112

Eastleigh

Hursley EMC Services

+44 (0) 23 8027 1111

Wismar

CEcert GmbH

+49 3841 2242 906

Essex

RN Electronics Ltd

01277 352219

Eiserfelder

EMC Testhaus Schreiber GmbH

+49 271 382702

Farnborough

QinetiQ

+44 (0) 1980 662 895

Stra ße

H+H High Voltage Technology GmbH

+49 2371 1853 0

High Wycombe Chomerics Europe

+44 (0) 1494 455 400

Hagen

HF-SHIELDING Joachim Broede GmbH

+49 54 05-99 99 04

Leicestershire Cre8 Associates Ltd

+44 (0) 1162 479787

Northamptonshire 3C Test Ltd

+44 (0) 1327 857500

GREAT BRITAIN Hampshire

TUV Product Service/BABT

+44 1489 558100

Merseyside

SGS International Certification Services

+44 1513 506666

GREECE Athens

EMC LLAS S.A.

30 210 7798365

NORWAY Oslo

Nemko, Inc.

47 229 60330

Spain Barcelona

GCEM-UPC

+34 93 401 10 21

Services: Emissions, ESD, Euro Certifications, FCC Part 15 & 18, Immunity

Intertek Semko AB

Services: CB/CAB/TCB, Emissions, ESD, Euro Certifications, FCC Part 15 & 18, Immunity, Product Safety

+44 (0)1327 857500

Oakley

Cranage EMC & Safety

+44 (0) 1630 658 568

Pontllanfraith Blackwood EMC, LTD

+44 (0) 1495 229 219

St. Helens

Rainford EMC Systems

+44 (0)1942296190

Services: Emissions, ESD, Euro Certifications, FCC Part 15 & 18, Immunity, MIL-STD 188/125, Product Safety, RTCA DO-160

Solihull

TRW Conekt

+44 (0) 121 627 4242`

Stebbing

Electromagnetic Testing Services Ltd

+44 (0) 1371 856 061

Wimborne

AQL EMC Limited

+44 (0) 1202 86 11 75 +44 (0) 1684 571700

OCEANIA

+46 8 750 00 00

AUSTRALIA

SWITZERLAND Berikon

Euro EMC Service

+41 566 33 73 81

Zürich

SGS International Certification Services

+41 44 445 16 80

Melbourne

EMC Technologies Pty Ltd

+613 9365 1000

Five Dock

EMI Solutions

0403 137652

NEW ZEALAND

THE NETHERLANDS Dordrecht

Holland Shielding Systems BV

Services: EMP, Lighting Effects, ESD, MIL-STD 188/125, MIL-STD 461/462, Shielding Effectiveness, Tempest

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Silverstone Circuit 3C Test Ltd.

Worcestershire TRaC Global (EMC Projects Ltd)

SWEDEN Kista

Northants

Christchurch

+31-7-8-6131366

Braco Compliance Ltd

+64 21 208 4303

interference technology

39

2012 emc test lab directory

Suppliers of Filters & Ferrites

Suppliers of Amplifiers

AR Worldwide RF/Microwave Instrumentation; Souderton, PA 215-723-8181; 800-933-8181; www.ar-worldwide.com

Fair-Rite Products Corp.; Wallkill, NY; 888-324-7748 www.fair-rite.com

CPI (Communications & Power Industries) Canada Inc.; Georgetown, ON, Canada; 905-877-0161; www.cpii.com/cmp Schurter Inc.; Santa Rosa, CA; 707-636-3000 www.schurterinc.com

Radius Power Inc.; Orange, CA; 714-289-0055 www.radiuspower.com

Instruments for Industry; Ronkonkoma, NY; 631-467-8400 www.ifi.com

Suppliers of Shielding

Suppliers of Antennas

Spira Manufacturing Corporation; N. Hollywood, CA 818-764-8222; www.spira-emi.com AH Systems; Chatsworth, CA; 818-998-0223 www.AHSystems.com

Suppliers of Conductive Materials

Spectrum Control; Fairview, PA; 814-474-2207 www.spectrumcontrol.com

Dontech Incorporated; Doylestown, PA; 215-348-5010 www.dontechinc.com

40 

interference technology

Tech-Etch, Inc.; Plymouth, MA; 508-747-0300 www.tech-etch.com

emc test & design guide 2011

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interference technology

41

testing & test equipment

A Ti m e - D o m a i n EMI M e a s u r e m e n t S y s t e m u p t o 26 G H z w i th M u lt i c ha n n e l A P D M e a s u r i n g F u n c t i o n

A Time-Domain EMI Measurement System Up to 26.5 GHz with Multichannel APD Measuring Function Hassan Hani Slim Christian Hoffmann Stephan Braun Arnd Frech GAUSS INSTRUMENTS GmbH Munich, Germany

Johannes A. Russer Institute for Nanoelectronics, Technische Universität München, Munich, Germany

I. INTRODUCTION he advances in radio systems in the past and their ongoing progress has been joined by advances in measurement systems and, hence, they require further development of measurement and specification standards. Electric and electronic systems have to be designed and realized such that the escape of unwanted electromagnetic energy into the environment is minimized. Electromagnetic compatibility denotes a situation where electrical and electronic systems are not mutually interfering by electric, magnetic or electromagnetic interference [1], [2]. The high bandwidth and the low power levels used in modern communication systems make them highly sensitive to electronic disturbances.

The conducted and radiated electromagnetic interference (EMI) of electric and electronic equipment has to be measured to certify that the equipment fulfills international standards of electromagnetic compatibility, e.g. defined by [3]. For the measurement of the EMI spectrum over a broad frequency

T

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band with high spectral resolution spectral analyzers or EMI receivers are used that have to fulfill certain requirements, e.g. defined in [4]. We developed a time-domain electromagnetic interference measurement system that uses ultra high-speed analogto-digital converters and real-time digital signal processing systems to enable ultra fast tests and measurements for electromagnetic compliance that fulfill the demand for measurements of today’s complex electronic equipment and systems [5], [6], [7], [8], [9].

Today, time domain electromagnetic interference measurement systems that use ultra high-speed analog-to-digital converters and real-time digital signal processing systems enable ultra fast tests and measurements for electromagnetic compliance for frequencies up to 26 GHz [7], [10]. Compared with traditional measurement receivers, the novel time-domain measurement systems reduce scan times by several orders of magnitude.

With such systems more complex measurements become feasible, like the complete angular characterization of a device under test (DUT) or the broadband search for low-level narrowband emissions. This allows to define new limits and new evaluation methods to validate equipment.

An interesting way to characterize stochastic EMI signals is to use the amplitude probability distribution (APD) [11]. The APD is defined as the part of time the measured envelope of an interfering signal exceeds a certain level [12]. The APD is closely related to the bit error rate of digital systems and, therefore, a definition of the emission limits on the basis of the APD emc Test & design guide 2011

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testing & test equipment

A Ti m e - D o m a i n EMI M e a s u r e m e n t S y s t e m u p t o 26 G H z w i th M u lt i c ha n n e l A P D M e a s u r i n g F u n c t i o n 0

10

−1

APD

10

−2

10

−3

10

−4

10 −10

−5

0 5 10 Amplitude [dBµV]

15

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Figure 1. Single channel APD block diagram.

Figure 2. APD graph of a single channel.

would be appropriate for digital equipment. Furthermore, using the APD, information such as the rms voltage or average power can be obtained [13]. The possibilities in describing the amplitude statistics by the APD function encourage the definition of a new type of limit-lines that depends on the statistical behavior. The APD has been used for the analysis of fluctuating signals [14] and multi-carrier systems like orthogonal frequency division multiplexing (OFDM) radars and communication systems [11]. However, a major drawback for evaluating the APD so far has been the time required to evaluate the emissions at a specific frequency

channel. In the presented time-domain system, the APD is evaluated and processed on several hundred channels simultaneously. This improvement and aforementioned advantages provided by using the APD function, encourage its incorporation in electromagnetic interference (EMI) measurement standards.

In this article we will describe the general concept of the APD function based analysis. Subsequently, we will introduce the real-time time-domain system that was used to implement APD function based analysis [10]. Then the new developed multi-channel APD will be described. Fi-

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emc Test & design guide 2011

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testing & test equipment

A Ti m e - D o m a i n EMI M e a s u r e m e n t S y s t e m u p t o 26 G H z w i th M u lt i c ha n n e l A P D M e a s u r i n g F u n c t i o n

Figure 3. Real-time time-domain multi-resolution system.

nally, a measurement using aviation emission detectors is performed and compared to CISPR detectors.

II. THE AMPLITUDE PROBABILITY DISTRIBUTION The amplitude probability distribution provides for a description of the signal amplitude statistics. For a random variable , a value (t) is allocated to each element t. In the case of emission measurements, the random variable (t) represents the amplitude of a measured emitted signal at a

Figure 4. Multi-stage broadband down-converter.

specific time t, and a specific frequency f. The frequency f depends on the intermediate frequency (IF) used, while the time t is the dwell time of the performed measurement. The APD of a certain value v is given by APD(v) = P((t) > v),

(1)

where P is the probability of (t) being above this threshold v. Eq. (1) can be represented by the block diagram shown in Fig. 1, described in CISPR 16-1-1 [4]. The measurement system’s input signal is sampled by an N-bit analog-to-digital converter (ADC), which provides for 2N distinct output levels. The following block is a RAM memory block which counts the number of occurrences of each amplitude level. Finally, the right-most block of Fig. 1 generates the APD function graph of each level according to (1). The measurement results of the APD of a single channel is plotted in Fig. 2. The minimum measurable probability of the APD, which is shown to be 10 -4 in the graph, depends on the number of samples measured which is proportional to the measurement time.

III. REAL-TIME TIME-DOMAIN MEASUREMENT SYSTEM Nowadays, various signal processing algorithms, such as for example the fast Fourier transform (FFT) algorithm, can be realized on configurable integrated circuits (IC) like field programmable gate arrays (FPGAs) or complex programmable logic devices (CPLDs). This yields 46

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emc Test & design guide 2011

testing & test equipment

S l i m , H o ff m a n n , B r a u n , F r e c h , R u s s e r

compact and affordable systems. Furthermore, this opened the possibility to realize real-time time-domain EMI measurement systems [15]. These novel time-domain EMI systems could realize additional measurement features that surpassed the systems available on the market till then.

The real-time time-domain EMI measurement system uses ultra-high speed analog-to-digital converters (ADCs) to sample the emission signals.

A wide band antenna in addition to a low pass filter precedes the ADCs, as shown in Fig. 3. Hence, we can detect the required bandwidth while avoiding aliasing effects due to high frequencies.

The ADCs are arranged in a multiresolution architecture to increase the dynamic range of the receiver [15]. The baseband of the receiver is 1.1 GHz, where frequencies above this limit are down-converted to the baseband by means of a down-converting frontend [16].

The sampled data is then accumulated in memory till the number of samples is sufficient for the required frequency resolution. Thereupon the samples in time-domain are transformed and stored into frequency bins using the short time fast Fourier transform (STFFT). The fast Fourier transform can benefit from repetition and symmetry properties for the discrete Fourier transform (DFT), and can be implemented into configurable integrated circuits. The frequency bins generated are applied afterwards to different detectors for being weighted, as illustrated in Fig. 3.

Figure 5. 6 - 26.5 GHz down-converter.

point (P1dB) of the radio-frequency (RF) front-end, the system achieves high sensitivity through an ultra-low system noise floor power spectral density of below -150 dBm/Hz and a high IF dynamic range exceeding 60 dB over the complete frequency range [10].

The basic block diagram of the

multi-stage broadband down-converter is shown in Fig. 4. Input signals in the frequency range from 1.1-6 GHz are converted to the band below 1.1 GHz and sampled by the ADCs. The down-converter includes an LNA to ensure high sensitivity. A single fixed preselection bandpass filter suppresses

A. Multi-Stage Broadband Down-Converter The sampling rate of current ADCs with high resolution is limited. Therefore, a multi-stage broadband downconverter was added to the system in order to increase the upper frequency limit to 18 GHz [9]. The current system enables measurements in the frequency range from 10 Hz to 26.5 GHz and adds the required IF-filters for the military and aviation EMC standards MIL-STD-461F [17] and DO-160F [18].

With integrated low-noise amplifiers (LNA) and a high 1 dB compression interferencetechnology.com

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testing & test equipment

A Ti m e - D o m a i n EMI M e a s u r e m e n t S y s t e m u p t o 26 G H z w i th M u lt i c ha n n e l A P D M e a s u r i n g F u n c t i o n

20

Magnitude [dBµV]

10

0

−10

Figure 7. Parallel channel APD measurement system.

−20

−30 0.15

5

10 15 20 Frequency [MHz]

25

bandpass filters with bandwidths between 3 and 5 GHz. The bands are switched via low-loss single-pole-quintuplethrow (SP5T) PIN-diode switches. An integrated, broadband LNA amplifies the input signal and increases the system sensitivity. The amplified signal is then down-converted by a broadband mixer with low conversion loss and a low phase-noise local oscillator signal generated by a phase locked loop (PLL)-synthesizer.

In order to measure low-power emission signals in the higher GHz-range, a high system sensitivity is needed. To decrease the system noise figure, passive components with low insertion loss have to be used in the preselection, as the noise figure of a passive device is equal to its insertion loss.

These components before the LNA are mainly defining the system noise figure F, according to [19]

30

Figure 6. Conducted emission measurement of a vacuum cleaner.

the image frequency band and acts as a preselection filter, increasing the dynamic range for broadband, noise-like and narrowband out-of-band input signals. Input signals above 6 GHz are in a first step down-converted to the range below 6 GHz. The block diagram of the 6-26.5 GHz down-converter is given in Fig. 5. The preselection consists of 5 ultra-wide

F2 − 1 F3 − 1 FN − 1 + + ... + N −1 , � G1 G1 G2 Gk

k=1

F = F1 +

(2)

where Gi is the available power gain of stage i and Fi is the noise figure of stage i. The implemented PIN-diode switches exhibit a low insertion loss below 3.6 dB for all paths. The isolation exceeds 30 dB over the complete frequency range from 6-26.5 GHz. B. Measurement Fig. 6 illustrates a conducted emission measurement performed on a vacuum cleaner power cord. Quasi-peak and CISPR-RMS-AVG detectors are used to weight the measured emission extracted using a 9 kHz IF-filter as required by CISPR 16-1-1. In addition, a positive detector is used to weight the emission by a 1 kHz IF-filter, required

by DO-160F. The lower noise level measured using the positive detector in comparison to the quasi-peak detector is due to the smaller equivalent noise bandwidth of the 1 kHz IF-filter.

IV. THE PARALLEL CHANNELS APD SYSTEM The schematic of the APD measuring function introduced in this paper is shown in Fig. 7. The frequency bins generated by the short time fast Fourier transform (STFFT) block are passed into a multichannel amplitude quantizer.

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emc Test & design guide 2011

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S l i m , H o ff m a n n , B r a u n , F r e c h , R u s s e r

40

PF Positive Average

1

Probability Function

Amplitude [dBµV]

30

20

10

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−10 2145

0 2150

2155 2160 Frequency [MHz]

2165

2170

Figure 8. Probability function measurement in comparison to positive and average detectors.

Figure 9. 3-D plot of an APD measurement evaluation with an emission limitline, taken from [20].

The quantized amplitude resolution in the new EMI measurement system can vary between 0.25 dB and 3 dB. The output of the quantizer per channel k determines the address i of the counter in the corresponding memory block RAM (i, k) that is incremented. The process of quantizing and incrementing counters is executed until the defined dwell time Td elapses, whereupon the APD(k) is calculated using the equation

that the APD curve is more powerful for evaluation than the single detectors in one graph. This could help in decreasing measurement time, while keeping all the valuable information of emissions which are being measured.

(3)

A. The Probability Function In addition to the APD plotting, the time-domain EMI measurement system can plot the probability function.

A measurement of a Wi-Fi signal was performed between 2.14 GHz and 2.175 GHz using the APD measuring function. For the purpose of comparison, the same measurement was repeated using positive peak and average detectors. The results of both measurements are plotted in Fig. 8. The average curve overlaps the part of the APD curve with the highest probability, while the positive detector curve overlaps the highest measured values of the emitted signal. The measurement was performed with a dwell time of 1 s and an amplitude resolution of 0.25 dB. An 120 kHz IF-filter defined in CISPR 16-1-1 and a frequency step of 50 kHz were used. It can be seen interferencetechnology.com

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testing & test equipment

A Ti m e - D o m a i n EMI M e a s u r e m e n t S y s t e m u p t o 26 G H z w i th M u lt i c ha n n e l A P D M e a s u r i n g F u n c t i o n

B. The New Limitline Definition The implementation of the multichannel APD measuring function provided the means for introducing new evaluation methods for emission measurements. In Fig. 9, a three dimensional surface is plotted representing a multichannel APD measurement of a DVB-T channel (taken from [20]).

Currently used limitlines are defined by their amplitude. In the 3-D graph of Fig. 9, they will be represented by a plane.

The new limitlines proposed are defined by their amplitude and probability. This will be beneficial for non-stationary signals. The new limitlines will be projected as a straight line into the APD 3-D spectrum. As an example, the limitline shown in Fig. 9 has an amplitude of 20 dBµV and a cumulative probability of 10 -2. The DUT fails at the frequencies where the spectrum covers the limitline. This is the case for frequencies below 758 MHz according to Fig. 9.

more depth of information about the measured emissions.

This system allows the definition of new limitline concepts which can be used e.g. to evaluate the fluctuation of signals.

ACKNOWLEDGMENT The authors would like to thank the Bayerische Forschungsstiftung for funding this project.

REFERENCES • [1] C. R. Paul, Introduction to Electromagnetic Compatibility. New York: John Wiley & Sons, 1992.

• [2] C. Christopoulos, Principles and Techniques of Electromagnetic Compatibility, ser. ISBN 0-8493–7892–3. CRC Press, 1995.

• [3] “Comité International Spécial des Perturbations Radioélectriques,” Feb. 2011. [Online]. Available: http://en.wikipedia.org/wiki/ Comité_International_Spécial_des_Perturbations_Radioélectriques • [4] “Specification for radio disturbance and immunity measuring apparatus and methods part 1-1: radio disturbance and immunity measuring apparatus – measuring apparatus,” CISPR16-1-1-am1 3rd ed., 2010.

• [5] F. Krug and P. Russer, “The time-domain electromagnetic interference measurement system,” IEEE Transactions on Electromagnetic Compatibility, vol. 45, pp. 330–338, 2003.

• [6] F. Krug, D. Müller, and P. Russer, “Signal processing strategies with the TDEMI measurement system,” IEEE Transactions on Instrumentation and Measurement, vol. 53, no. 5, pp. 1402–1408, 2004.

• [7] S. Braun and P. Russer, “A low-noise multiresolution high-dynamic ultra-broad-band time-domain EMI measurement system,” IEEE Transactions on Microwave Theory and Techniques, vol. 53, no. 11, pp. 3354–3363, 2005.

• [8] S. Braun, T. Donauer, and P. Russer, “A real-time time-domain EMI measurement system for full-compliance measurements according to CISPR 16-1-1,” IEEE Transactions on Electromagnetic Compatibility, vol. 50, no. 2, pp. 259–267, 2008.

• [9] C. Hoffmann and P. Russer, “A real-time low-noise ultra-broadband time-domain EMI measurement system up to 18 GHz,” IEEE Transactions on Electromagnetic Compatibility, vol. 53, 2011.

• [10] C. Hoffmann, A. Boege, and P. Russer, “A low-noise time-domain EMI measurement system for measurements up to 26 GHz,” Proceedings of the 30th URSI General Assembly 2011, Istanbul, Turkey, 13–20 August, 2011.

• [11] K. Wiklundh, “Relation between the amplitude probability distribution of an interfering signal and its impact on digital radio receivers,” IEEE Transactions on Electromagnetic Compatibility, vol.

48, pp. 537–544, 2006.

• [12] Y. Yamanaka and T. Shinozuka, “Measurement and estimation of BER degradation of PHS due to electromagnetic disturbances from microwave ovens,” Electronics and Communications in Japan (Part I: Communications), vol. 81, no. 2, pp. 55–63, 1998 • [13] M. Kanda, “Time and amplitude statistics for electromagnetic noise in mines,” IEEE Transactions on Electromagnetic Compatibility, vol. 17, pp. 122–129, 1975.

• [14] K. Gotoh, Y. Matsumoto, S. Ishigami, T. Shinozuka, and M. Uchino, “Development and evaluation of a prototype multichannel APD measuring receiver,” Proceedings of the 2007 IEEE International Symposium on Electromagnetic Compatibility, pp. 1–36, 2007.

• [15] S. Braun, M. Al-Qedra, and P. Russer, “A novel realtime time-

V. CONCLUSION A real-time time-domain EMI measurement system from 10 Hz up to 26.5 GHz was presented. This system satisfies the requirements for valid emission measurement according to CISPR 16-1-1, MIL-STD-461F and DO-160F standards. The EMI measurement system is equipped with a multichannel APD measuring function. It has been shown that the multichannel APD measuring function based analysis can be implemented on current technology and that it can give

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testing & test equipment

S l i m , H o ff m a n n , B r a u n , F r e c h , R u s s e r

•

• • • •

domain EMI measurement system based on field programmable gate arrays,” in Proceedings of the 17th International Zurich Symposium on Electromagnetic Compatibility, 2006, EMC Zurich 2006, Singapore, Feb. 2006, pp. 501–504.

[16] C. Hoffmann and P. Russer, “A time-domain system for CISPR 16-1-1 compliant measurements above 1 GHz,” in Proceedings of the Asia-Pacific Symposium on Electromagnetic Compatibility, Jeju Island, Korea May, 16–19, 2011. APEMC 2011, 2011, pp. 1–4.

[17] “Requirements for the control of electromagnetic interference characteristics of subsystems and equipment,” MIL-STD-461F, 2010.

[18] “Environmental conditions and test procedure for airborne equipment,” DO-160F, 2007.

[19] W. B. Davenport and W. L. Root, An Introduction to the Theory of Random Signals and Noise. Wiley-IEEE Press, Oct. 1987.

[20] H. H. Slim, C. Hoffmann, S. Braun, and P. Russer, “A novel multichannel amplitude probability distribution for a time-domain EMI measurement system according to CISPR 16-1-1,” EMC Europe 2011, York, UK, 2011.

frequency engineering and electronic systems. He received the Bachelor of Science and the Dipl.-Ing. degree both from the Technische Universität München in 2005 and 2006, respectively. After finishing his diploma thesis in the field of near-infrared spectroscopy at the Swiss Federal Institute of Technology, Zurich, Switzerland, he joined the Institute for High-Frequency Engineering at the Technische Universität München as a research assistant working towards the Dr.-Ing. degree. He is co-founder and managing director of GAUSS INSTRUMENTS GmbH, working in the field of EMC and RF measurement instrumentation and highspeed digital signal processing. He can be reached at frech@tdemi.com.

Johannes A. Russer received his Dipl.-Ing. (M.S.E.E.) degree in electrical engineering and information technology from the Universität Karlsruhe, Germany, in 2003. In 2004 he joined the University of Illinois at UrbanaChampaign as a research assistant where he received his Ph.D.E.E. degree in 2010. From 2007 to 2010 he has been working for Qualcomm Inc. as an intern. Since 2010 he is a Postdoctoral Research Fellow at the Institute of Nanoelectronics of the Technische Universität München (TUM), Germany.

The current research interests of Johannes A. Russer include the modeling of multiphysics problems, numerical electromagnetics and stochastic electromagnetic fields. He is a member of IEEE, VDE and of the Eta Kappa Nu honor society. He can be reached at jrusser@tum.de. n

Hassan H. Slim received the Bachelor of Engineering (B.E.) degree in Computer and Communication Engineering in 2005 from Business and Computer University College (BCU) in Beirut, Lebanon. He obtained his Masters of Science (M.Sc.) degree in Microwave Engineering in 2007 from the Technische Universität München (TUM), Germany. Since 2008 he is working towards his Dr.-Ing. degree at the Institute for High-Frequency Engineering at TUM, Germany under the supervision of Prof. Dr. Peter Russer. His current research is focused on investigations of electromagnetic compatibility (EMC) techniques above 1 GHz, in addition to signal processing techniques and automation routines applied in EMC. Since June 2011 he is working with GAUSS INSTRUMENTS GmbH as a software design engineer. He is a member of IEEE. He can be reached at hslim@tdemi.com.

Christian Hoffmann received the Dipl.-Ing. degree in Electrical Engineering from the Technische Universität München (TUM), Munich, Germany, in 2008. From 2008 to 2011 he was working at the Institute for High-Frequency Engineering at TUM, Germany as a research assistant.

He is currently employed as an RF Design Engineer at GAUSS INSTRUMENTS GmbH, Munich, Germany, where he is working towards the Dr.-Ing. degree. His research interests include measurement techniques in the microwave and millimeter wave regime, microwave and millimeter wave passive and active circuits and digital signal processing.

His research is focused on the investigation of electromagnetic compatibility in time-domain above 1 GHz. Christian Hoffmann is a member of the IEEE and VDE. He can be reached at choffmann@tdemi.com.

Stephan Braun studied Electrical Engineering at Munich University of Technology (TUM), and received his Dipl.-Ing. degree in 2003.

From 2003-2009 he was research assistant at the Institute for HighFrequency Engineering, where he received his Dr.-Ing. degree in 2007.

Dr. Braun is now managing director of GAUSS INSTRUMENTS. His research interests are EMC and microwave measurement technology, as well as RF-circuits and digital signal processing. Further interests are fast digital circuits and configurable digital logic. Dr. Braun is Member of the VDE and IEEE. He can be reached at braun@tdemi.com.

Arnd Frech studied electrical engineering at the Technische Universität München (TUM), Munich, Germany with focus on highinterferencetechnology.com

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surge & transients

Tr a n s i e n t V o lta g e S u p p r e s s o r s f o r A u t o m o t i v e Elec tronic Prot ec tion

Transient Voltage Suppressors (TVS) for Automotive Electronic Protection

SOO MAN (SWEETMAN) KIM Vishay Intertechnology, Inc. Malvern, Pennsylvania, USA

A

major challenge in automotive design is protecting electronics – such as control units, sensors, and entertainment systems – against damaging surges, voltage transients, ESD, and noise that are present on the power line. Transient voltage suppressors (TVS) are ideal solutions for automotive electronic protection and have several important parameters for these applications, including power rating, stand-off voltage, breakdown voltage, and maximum breakdown voltage. Following are definitions for these parameters.

POWER RATING The power rating of a TVS is its surgeabsorbing capability under specific test or application conditions. The industrial-stanFigure 1. Test waveform of TVS (Bellcore 1089).

Bellcore 1089 represented the closest approximation to the medium- and high-power conditions encountered by TVS devices at the time when they were developed and proved an easier basis for the range of purposes and applications in which these devices are used than ISO7637-2 [2] or JASO A-1 [3].

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dard test condition of 10 μs/1000 μs pulse form (Bellcore 1089 spec. [1]) is shown in Figure 1. This test condition differs from the TVS transient voltage absorbing capability test condition of 8 μs/20 μs pulse form, as shown in Figure 2.

BREAKDOWN VOLTAGE (VBR) The breakdown voltage is the voltage at which the device goes into avalanche breakdown, and is measured at a specified current on the datasheet.

MAXIMUM BREAKDOWN VOLTAGE (VC: CLAMPING VOLTAGE) The clamping voltage appears across the TVS at the specified peak pulse current rating. The breakdown voltage of a TVS is measured at a very low current, such as 1 mA or 10 mA, which is different from the actual avalanche voltage in application conditions. Thus, semiconductor manufactures specify the typical or maximum breakdown voltage in large current.

STAND-OFF VOLTAGE (V WM): WORKING STAND-OFF REVERSE VOLTAGE The stand-off voltage indicates the maximum voltage of the TVS when not in breakdown, and is an important parameter of protection devices in circuits that do not operate under normal conditions. In automotive applications, some regulation of the automotive electronics is provided by “jump-start protection.” This condition supplies 24 V DC in 10 minutes to 12-V type electronics, and 36 V DC in 10 minutes to

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surge & transients

Tr a n s i e n t V o lta g e S u p p r e s s o r s f o r A u t o m o t i v e Elec tronic Prot ec tion

Figure 3. Parameters of voltage and current.

Figure 2. Test waveform of TVS. ESD protection devices are traditionally tested and specified for their ability to absorb an 8 Îźs/20 Îźs surge pulse since this allows better differentiation between the abilities of various devices than the IEC61000-4-2 pulse test, which all devices should be able to pass regardless of their stated ESD capability.

24-V type electronics without damage or malfunction of the circuit. Thus, the stand-off voltage is one of the key parameters in TVS for automotive electronics.

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Figure 4. Typical vehicle power bus.

emc Test & design guide 2011

surge & transients

Tr a n s i e n t V o lta g e S u p p r e s s o r s f o r A u t o m o t i v e Elec tronic Prot ec tion Figure 6. For ISO-7637-2 test conditions, the standard condition is a VS range of 65 V to 87 V, and Ri (line impedance) range of 0.5 Ω to 4 Ω.

Figure 5. (right) Output voltage of alternator in load dump condition.

PRIMARY PROTECTION OF THE AUTOMOTIVE POWER LINE (LOAD DUMP) Automotive electronics, such as electronic control units, sensors, and en-

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tertainment systems, are connected to one power line. The power sources for these electronics are the battery and alternator, both of which have unstable output voltages that are subject to temperature, operating status, and other conditions. Additionally, ESD, spike noise, and several kinds of transient and surge voltages are introduced into the power and signal line from automotive systems that use solenoid loads, such as fuel injection, valve, motor,

electrical, and hydrolytic controllers.

WHAT IS LOAD DUMP? The worst instances of surge voltage are generated when the battery is disconnected when the engine is in operation, and the alternator is supplying current to the power line of the vehicle. This condition is known as “load dump,” and most vehicle manufacturers and industry associations specify a maximum voltage, line impedance, and time duration for this load dump status, as shown in Figure 5. The source impedance for load dump is higher than for the normal transient tests because the battery is disconnected and only the alternator, whose internal coil acts like a current limit resistor, is sourcing the power.

The following general considerations of the dynamic behavior of alternators during load dump apply: a) The internal resistance of an alternator, in the case of load dump, is mainly a function of alternator rotational speed and excitation current. b) The internal resistance Ri of the load dump test pulse generator shall be obtained from the following relationship: Ri = ( 10 X Unom X Nact ) / ( 0.8 X Irated X 12,000 min -1 ), where Unom is the specified voltage of the alternator; Nact is the specified current at an alternator speed of 6,000 min-1 (as given in ISO 8854); Irated is the actual alternator speed, in reciprocal minutes.

Two well-known tests simulate this condition: the U.S.’s ISO-7637-2 Pulse 5 and Japan’s JASO A-1 for 14-V powertrains and JASO D-1 for 27-V emc Test & design guide 2011

surge & transients

K im V TOTAL (Vp) (V) JASO A-1

Vs V

70 88

ISO 7637-2 Pulse 5

78.5 to 100.5

65 to 87

VA V

RI ()

TIME (ms)

CYCLE TIME

12.0

0.8

200

1

12.0

1.0

200

1

13.5

0.5 to 4.0

400

1

Table 1. Major load dump test conditions for 14-V powertrains.

powertrains. In this section we review the application of TVS for load dump in 14-V powertrains.

SPECIFICATION AND RESULTS OF LOAD DUMP TESTS The U.S.’s ISO-7637-2 Pulse 5 and Japan’s JASO A-1 tests for 14-V powertrains are simulated in Table 1.

Some vehicle manufacturers apply different conditions for the load dump test based on ISO-7637-2 Pulse 5. The peak clamped current of the load dump TVS will be estimated by the following equation: Calculation for peak clamping current IPP= (Vin– VC) ⁄ Ri IPP: Peak clamping current Vin: Input voltage VC: Clamping voltage Ri: Line impedance The current and voltage waveforms of Vishay’s SM5S24A

Figure 7a. Clamped voltage and current of SM5S24A in ISO 7637-2 test.

Figure 7b. Clamped voltage and current of load dump TVS failures in ISO7637-2 test.

Figure 7c. Maximum clamping capability of Vishay load dump TVS in ISO7637-2 test.

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surge & transients

Tr a n s i e n t V o lta g e S u p p r e s s o r s f o r A u t o m o t i v e Elec tronic Prot ec tion

in the ISO-7637-2 test of 87V Vs, 13.5V V batt., 0.75 Ohm Ri and 400ms pulse width as shown in Figure 7A. In Figure 7B the clamped voltage and current of load dump TVS fail in the ISO-7637-2 test of 87V Vs, 13.5V V batt., 0.5 Ohm Ri and 400ms pulse width because the device was over-dissipated. The clamping voltage drops to near zero, and the current passed through the device is increased to the maximum allowed by the line impedance.

The maximum clamping capability of Vishay load dump TVS of ISO-7637-2 pulse 5 test condition with 13.5V V batt

and 400ms pulse width is shown in Figure 7C. To prevent failure, such as that shown in Figure 7B, it is important to respect the maximum rating of the TVS. PROTECTION AGAINST NEGATIVE-GOING TRANSIENTS AND REVERSED SUPPLY VOLTAGE There are two kinds of load dump TVS for the primary protection of automotive electronics: epitaxial and non-epitaxial.

Both product groups have similar operating breakdown characteristics in reverse bias mode. The difference is that epitaxial TVSs have low forward voltage drop (VF) characteristics in forward mode, and non-epitaxial TVSs have relatively high VF under the same conditions.

This characteristic is important to the reverse voltage supplied to the power line. Most CMOS ICs and LSIs have very poor reverse voltage capabilities.

The gates of MOSFETs are also weak in reverse voltage, at - 1 V or lower. In the reversed power input mode, the voltage of the power line is the same as the voltage of the TVS VF. This reverse bias mode causes electronic circuit failure. The low forward voltage drop of EPI PAR TVSs is a good solution to this problem.

Another method to protect circuits from reversed power input is utilizing a polarity protection rectifier into the power line, as shown in Figure 8.

A polarity protection rectifier should have sufficient forward current ratings, and forward surge and reverse voltage capabilities.

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interference technology

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SECONDARY PROTECTION OF THE AUTOMOTIVE POWER LINE The primary target of protection circuits in automotive systems is high surge voltages, but the clamped voltage is still high. Secondary protection is especially important in 24- V powertrains, such as found in trucks and vans. The main reason for this is the maximum input voltages for most regulators and dc-to-dc converter ICs for automotive applications are 45 V to 60 V. For this kind of application, using secondary protection, as shown in Figure 9, is recommended.

Adding resistor R onto the power line reduces the transient current, allowing smaller power-rating TVSs as the secondary protection. Current requirements for microprocessor and logic circuits in electronic units are emc Test & design guide 2011

surge & transients

K im

Figure 8. Reverse bias status.

Figure 9. Secondary protection circuit.

150 mA to 300 mA, and the minimum output voltage of a 12-V battery is 7.2 V at -18°C, or 14.4 V for a 24-V battery under the same conditions. In a 24-V battery under the above conditions, the supply voltage at a 300-mA load is 8.4 V at R = 20 Ω, and 11.4 V at R = 10 Ω at a minimum voltage of 14.4 V (24-V battery voltage in - 18 °C).

V L = (Vmin ⁄ (Vmin ⁄ IL)) × ((Vmin ⁄ IL) – R) V L: Voltage to load Vmin: Minimum input voltage IL: Load current R: Resistor value Power rating of R = I2R This supply voltage is higher than the minimum input voltages for most voltage regulators and DC/ DC converter ICs to avoid wrong operation of circuit by low voltage input.

While safety and reliability issues are important considerations in automotive systems, they are beyond the scope of this article.

• [5] IEC 61000-4-5 International Standard Electromagnetic Compatibility (EMC) – Part 4-5: Testing and measurement techniques, surge immunity test. www.iec.ch Soo Man (Sweetman) Kim studied electronic engineering at YoungNam University in Korea and has worked for Vishay General Semiconductor on field application engineering and product marketing applications for rectifier and TVS devices since 1987. n

CONCLUSION In this article, we’ve described all the transients and their modes that can damage automotive electronic systems. We’ve gone on to discuss the important parameters of TVSs, and have demonstrated that with the appropriate specifications, these devices can protect circuits against all transients and the load dump condition.

References • [1] Bellcore 1089, https://www.scte.org • [2] ISO/DIS-7637-2.3 2004 Road vehicles – Electrical disturbances from conduction and coupling – Part 2. Electrical transient conduction along supply lines only. www.iso.ch • [3] JASO D 001-94 Japanese Automobile standard, http:// www.jsae.or.jp • [4] ES-XW7T-1A278 - AC Component and Subsystem Electromagnetic Compatibility, Worldwide Requirements and Test Procedures, Ford Motor Company, http://www.fordemc.com

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smart grid

EMC a n d t h e S M A R T G RID

EMC and the Smart Grid

William A. Radasky Metatech Corporation Goleta, California, USA

I

n April 2011 this author published an article dealing with the threats and potential impacts to the future U.S. Smart Grid from high power electromagnetic (HPEM) threats including High-altitude Electromagnetic Pulse (HEMP) from a nuclear detonation in space over the U.S., Intentional Electromagnetic Interference (IEMI) from terrorists or criminals who may attack and create regional blackouts using electromagnetic weapons, and finally from an extreme geomagnetic storm (initiated by solar activity) that could create damage to the high-voltage electric grid [1]. This author has previously referred to these three electromagnetic environments as a “triple threat” [2].

In this article I will summarize the efforts underway to deal with all electromagnetic threats (including EMC) to the Smart Grid under the Smart Grid Interoperability Panel (SGIP). This author is a participant in this effort and feels there is value in informing those with interests in the EMC field to know the progress of that effort.

This article begins with brief “definitions” of the current power system and the future Smart Grid, followed by an explanation of the SGIP program in general and the EMC activities in particular. At the end of this article some information concerning the approach to determine the appropriate electromagnetic environments 60

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for new Smart Grid electronic equipment is provided.

It should be emphasized that the EMC work in SGIP is not finished, and this information should be considered as a “snapshot” of the current situation.

What is the Smart Grid?

The basic electric power grid today consists of basic elements of generation, transmission, distribution and users (residential, commercial and industrial) as shown in Figure 1. Note that the figure indicates the presence of wind power at the subtransmission level and solar panels at both commercial and residential facilities. However, as wind power and solar proliferate and become a higher percentage of power generation, their variability will make it more difficult to keep energy supply and demand in balance. Due to the pressures from many stakeholders, there is a rush to push renewable energy to much higher levels than we have today.

In order to cope with the increased variable power generation and the fact that many of these “power plants” are not always controlled by a control center (e.g., roof top solar systems) there will be a need for more sensors and controls in the power network, both at the transmission and distribution level. It will be important for the utility controlling the voltage and frequency of the network to have situational awareness of the connected power system. This means that new sensors and higher speed communications networks will be needed as shown emc Test & design guide 2011

smart grid

EMC a n d t h e S M A R T G RID

of this article on the Electromagnetic Interoperability Issues Working Group (EMIIWG).

The Scope and Tasks of the EMIIWG in SGIP After considerable discussion and presentation of EMC issues that should be dealt with as part of the SGIP process, the SGIP decided to form a new working group in the fall of 2010. The Chairman of this working group is Dr. Galen Koepke from NIST in Boulder, Colorado. The kickoff meeting of the EMIIWG was held on 1 November 2010. The working group was assigned the following scope and tasks [7].

Figure 1. Basic elements of a power grid [3].

in Figure 2.

One of the new types of “sensors” to be used in a Smart Grid is the “Smart Meter” that is electronic in nature and possesses a communications capability to provide information to the power utility with respect to power usage and also where downed power lines may be located due to a storm or other event.

These meters are being installed at many locations throughout the country, although the actual design of these meters may vary in different parts of the country.

From an EMC point of view the Smart Grid introduces some new elements that should be considered from an EMC point of view. The design and placement of sensors with varying bandwidths may be affected by the electromagnetic environment present.

While the electric power industry is well aware of the severe electromagnetic environment found in high and medium voltage substations, there may not be as much understanding of the appropriate EM environment in a wind farm, or in an industrial manufacturing area. In addition the presence of new transmitters being introduced create the potential of interference. EMC immunity specifications are also not routine in the U.S. for home appliance manufacturers, who may not account 62

interference technology

for the more complex EM environment present today in the home. Finally the performance criteria for equipment operation in the presence of EM environments are different when there is the need for equipment to communicate without human intervention, in addition to operate.

The SGIP Program In 2007 NIST was given the “primary responsibility to coordinate development of a framework that includes protocols and model standards for information management to achieve interoperability of smart grid devices and systems.” [5] Interoperability is defined by NIST as the ability of diverse systems and their components to work together – it enables integration, effective cooperation, and two-way communication among the many interconnected elements of the electric power grid [4].

In order to provide an open, consensus-based process, an organizational structure was developed known as the Smart Grid Interoperability Panel (SGIP). Figure 3 illustrates the organization of the SGIP with a figure that has been updated to include a new EMC related working group [4,6].

While there are many parts to the SGIP, we are going to focus in the rest

Scope This Working Group will investigate enhancing the immunity of Smart Grid devices and systems to the detrimental effects of natural and man-made electromagnetic interference, both radiated and conducted. The focus is to address these electromagnetic compatibility (EMC) issues and to develop recommendations for the application of standards and testing criteria to ensure EMC for the Smart Grid, with a particular focus on issues directly related to interoperability of Smart Grid devices and systems, including impacts, avoidance, generation and mitigation of and immunity to electromagnetic interference. These recommendations from the Electromagnetics Interoperability Issues Working Group can be considered by the SGIP for follow-on activity (PAP creation, SGTCC action, etc.). With its focus on interoperability, this effort is not a general review of electromagnetics and electric power related issues, such as power quality, which are being addressed in different groups outside the SGIP. Tasks 1. Review potential electromagnetic issues and the existing state of EMC of the power grid and associated systems, including current and proposed Smart Grid enhancements.

2. Segment the Smart Grid devices and systems and electromagnetic environments into a minimal set of categories for which electromagnetic emc Test & design guide 2011

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EMC a n d t h e S M A R T G RID

Figure 2. Communications links (shown in blue) that may be needed as part of a Smart Grid [4].

issues and EMC requirements can be identified. These categories should

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be compatible with the environment classifications of IEC 61000-2-5 where possible.

3. Prioritize or rank the categories in (2) according to the potential impact on Smart Grid reliability. The priorities should consider the extent and severity of possible failures and the availability requirements for the relevant interface as defined in NISTIR 7628.

4. Identify and/or propose EMC terminology and definitions applicable to the Smart Grid and compatible with international standards.

5. Identif y and compile the source-victim matrix for each category identified in (2).

6. Identif y or develop EMC performance metrics for systems in each category identified in (2).

7. Identify appropriate EMC standards and requirements to meet performance metrics.

8. Identify areas where EMC standards are not available and appropriate SDOs where such standards should be developed.

9. Identify and propose Priority Action Plans to address standards or guidelines in high priority categories if needed.

10. Propose strategic recommendations for EMC of Smart Grid systems, beginning with the highest priority categories. These recommendations should reflect a long-term strategy to maintain EMC as the Smart Grid evolves.

11. Consider the need, and if appropriate, the nature of a conformity assessment program for EMC for coordination with the SGIP Smart Grid Testing and Certification Committee.

In terms of technical progress, the EMC work has been divided into two focus teams: Power Delivery and Power Customer. The separation point is the customer meter. The two teams are contributing to a report to the SGIP that will identify and recommend existing EMC standards that are appropriate for the various equipment locations and will further identify standards that are not adequate or even available for the purposes of Smart Grid. It is planned that the recommendations from the EMIIWG will be included in the next release of the SGIP Framework.

It is beyond the scope of this paper to discuss all of the items in the task list, but instead the focus will be on task 2, which involves the determination of the appropriate EM environemc Test & design guide 2011

smart grid

EMC a n d t h e S M A R T G RID

Figure 3. Organization of SGIP [4,6].

ment for Smart Grid equipment.

The Electromagnetic Environment One of the key aspects to the work of

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the EMIIWG is to determine whether adequate EMC immunity standards exist for future Smart Grid equipment that are consistent with the electromagnetic environment where they are intended to operate. As this author was a member of IEC TC 77/WG 13 that prepared Edition 2 of IEC 610002-5, “Description and classification of electromagnetic environments” [8], some discussion of the approach taken is presented here.

IEC 61000-2-5 Edition 2: • P rovides information about EM phenomena expected at different locations • Introduces the approach to describe electromagnetic phenomena by their disturbance degrees • Classifies the EM environments into different types of locations and describes them by means of attributes • C ompiles tables of disturbance levels for EM phenomena that are considered relevant for those types of locations The location classes in Edition 2 of 61000-2-5 have been consolidated to three locations including Residential, Commercial/Public, and Industrial.

Edition 1 defined more locations, but it was decided to provide more detailed environments for fewer locations. Also in the IEC there is a separate EMC generic specification to cover power

system electronics, IEC 61000-6-5 [9].

It is likely that IEC 61000-2-5 will be more applicable to the power customer aspect of the EMIIWG, while IEC 61000-6-5 and other IEC and IEEE product standards will be more applicable to the Power Delivery aspect of the work. As progress has been more rapid on the power customer side of the Smart Grid problem, the remaining discussion will only cover the environment information in IEC 61000-2-5.

The process used in IEC 61000-2-5 involved three major steps: 1) Define the location classes with regard to the types of exposures (both conducted and radiated) and the distances expected from particular types of emitters.

2) C ompile a comprehensive list of radiated and conducted phenomena and disturbance levels along with formulas to compute field levels where appropriate (include formulas for near-field exposure).

3) C ombine the results to develop recommendations for disturbance levels for a given “location” for all applicable phenomena.

Figure 4 illustrates this process in graphical form.

It should be mentioned that two main improvements were made with regard to phenomena in IEC 610002-5 Edition 2. The first was to ensure that all conducted phenomena were updated since the last edition fifteen years ago, to include for example, more recent power harmonic environments due to switched mode power supplies.

In the area of radiated phenomena, significant work was done with the support of ITU-T to keep up with new broadcast services (frequencies and power levels) and other radio services such as RFID. While the process to identify the appropriate EM environments, immunity test standards and equipment performance criteria when tested are well underway in the EMIIWG for both the power customer and the power delivery aspects of the EMC problem, the results are not yet final. It is expected that after the EMIIWG report is finalized and sent to the SGIP, then further details can be provided to interested emc Test & design guide 2011

smart grid

Radask y

•

• • •

•

•

•

Figure 4. Graphical approach for determining disturbance levels for all phenomena at a given location [8].

readers.

Summary This article has presented some background to the problem of EMC and the Smart Grid in the United States. The SGIP program and the scope and tasks of the EMIIWG have been summarized for the reader. Links are provided in the references for those who have interest to explore further. This article also discusses the approach used by the EMIIWG to develop an understanding of the EM environment that would be present at locations where Smart Grid interferencetechnology.com

equipment may be placed, so that it will be possible to determine the adequacy and availability of EMC immunity test standards for the Smart Grid Program.

References • [1] Radasky, W. A., “High Power Electromagnetic (HPEM) Threats to the Smart Grid,” Interference Technology EMC Directory and Design Guide, April 2011.

• [2] Rada sk y, W. A ., “Protec t ion of Commercial Installations from the “Triple Threat” of HEMP, IEMI, and Severe Geo

magnetic Storms,” Interference Technology EMC Directory and Design Guide, April 2009.

[3] Olofsson, M., A. McEachern and W. Radasky, “EMC in Power Systems Including Smart Grid,” APEMC, Jeju Island, Korea, May 2011.

[4] http://www.nist.gov/smartgrid/nistandsmartgrid.cfm [5] “The Energy Independence and Security Act of 2007,” U.S. Public Law 110-140.

[6] Koepke, G., “N IST Sma r t Grid Framework and the SGIP EMII Working Group,” Tutorial Presentation at the IEEE International EMC Symposium, Long Beach, California, August 2011.

[7] http://collaborate.nist.gov/twikisggrid/bin/view/SmartGrid/ElectromagneticIssuesWG [8] IEC 61000-2-5 Edition 2, “Description and classification of electromagnetic environments,” International Electrotechnical Commission, May 2011.

[9] IEC 61000-6-5, “Immunity for power station and substation environments,” International Electrotechnical Commission, July 2001.

Dr. William A. Radasky, Ph.D., P.E., received his Ph.D. in Electrical Engineering from the University of California at Santa Barbara in 1981.

He has worked on high power electromagnetics (HPEM) applications for more than 43 years.

In 1984 he founded Metatech Corporation in Goleta, California, which performs work for customers in government and industry. He has published over 400 reports, papers and articles dealing with transient electromagnetic environments, effects and protection during his career.

He is Chairman of IEC SC 77C and IEEE EMC Society TC-5. He is an EMP Fellow and an IEEE Life Fellow.

Dr. Radasky is very active in the field of EM standardization, and he received the Lord Kelvin Award from the IEC in 2004 for outstanding contributions to international standardization.

He served as Chairman of the IEC Advisory Committee on EMC (ACEC) from 1997 to 2008. He is currently working with the EMC Working Group commissioned by the Smart Grid Interoperability Panel (SGIP) to evaluate the performance of Smart Grid communications in the face of everyday EM environments and interference caused by HPEM threats. n

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design

G r o u n d i n g f o r t h e C o n t r o l o f E MI

Designing Electronic Systems for EMC: Grounding for the Control of EMI

William G. Duff SEMTAS Corp.

Fairfax Station, Virginia, USA

T

here are two primary reasons for grounding devices, cables, equipments, and systems. The first reason is to prevent shock and fire hazards in the event that an equipment frame or housing develops a high voltage due to lightning or an accidental breakdown of wiring or components.

The second reason is to reduce EMI effects resulting from electromagnetic fields, common impedance, or other forms of interference coupling.

Historically, grounding requirements arose from the need to provide protection from electrical faults, lightning, and industrially generated static electricity. Because most power-fault and lightning control relies on a low-impedance path to earth, all major components of an electrical power generation and transmission system were earth grounded to provide the required low-impedance path. As a result, strong emphasis was placed on earth grounding of electrical equipment, and the overall philosophy was “ground, ground, ground” without regard to other problems, such as EMI, that may be created by this approach.

When electronic equipments were introduced, grounding problems became evident.

These problems resulted from the fact that the circuit and equipment grounds often provided the mechanism for undesired EMI

coupling. Also, with electronic systems, the ground may simultaneously perform two or more functions, and these multiple functions may be in conflict either in terms of operational requirements or in terms of implementation techniques. For example, as illustrated in Figure 1, the ground network for an electronic equipment may be used as a signal return, provide safety, provide EMI control, and also perform as part of an antenna system.

Therefore, in order to avoid creating EMI problems, it is essential to recognize that an effective grounding system, like any other portion of an equipment or system, must be carefully designed and implemented.

Grounding is a system problem and in order for a grounding arrangement to perform well it must be well conceived and accurately designed and implemented. The grounding configurations must be weighed with regard to dimensions and frequency, just like any functional circuit.

The objective of this chapter is to help engineers, designers, and technicians to optimize the functionality and reliability of their equipment by providing an orderly systems approach to grounding. Such an approach is highly preferable to the empirical and sometimes contradictory approaches that are often employed.

Characteristics of Grounding Systems Ideally, a ground system should provide a zero-impedance path to all signals for

This article is excerpted from "Designing Electronic Systems for EMC," by William G. Duff, June 2011, SciTech Publishing, www.scitechpub.com/emc/

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emc Test & design guide 2011

design

G r o u n d i n g f o r t h e C o n t r o l o f E MI

Figure 1. The multiple functions of grounds.

which it serves as a reference. If this were the situation, signal currents from different circuits or equipments that are connected to the ground could return to their respective sources without creating unwanted coupling between the circuits or equipments. Many interference problems occur because designers treat the ground as ideal and fail to give proper attention to the actual characteristics of the grounding system. One of the primary reasons that designers treat the ground system as ideal is that this assumption is often valid from the standpoint of the circuit or equipment design parameters (i.e., the impedance at power or signal frequen-

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Figure 2. Ground can be a misleading, ambiguous term if one does not consider its electrical parameters.

emc Test & design guide 2011

Duff

cies is small and has little or no impact on circuit or equipment performance).

However, the non-ideal properties of the ground must be recognized if EMI problems are to be avoided.

Impedance Characteristics Every element (conductor) of a grounding system, whether it be for power grounding, signal grounding, or lightning protection, has properties of resistance, capacitance, and inductance.

Shields and drain wires of signal cables, the green wire power safety ground, lightning down conductors, transformer vault buses, structural steel members — all conductors have these properties. The resistance property is exhibited by all metals. The resistance of a ground path conductor is a function of the material, its length, and its cross-sectional area. The capacitance associated with a ground conductor is determined by its geometric shape, its proximity to other conductors, and the nature of the intervening dielectric.

The inductance is a function of its size, geometry, length, and, to a limited extent, the relative permeability of the metal. The impedance of the grounding system is a function of the resistance, inductance, capacitance, and frequency.

Because the inductance properties of a conductor decrease with width and increase with length, it is frequently recommended that a length-to-width ratio of 5:1 be used for grounding straps. This 5:1 length-to-width ratio provides a reactance that is approximately 45 percent of that of a straight circular wire.

The impedance of straight circular wires is provided as a function of frequency in Table 5.1 for several wire gauges and lengths. Typical ground plane impedances are provided in Table 5.2 for comparison. Note that for typical length wires, ground plane impedances are several orders of magnitude less than those of a circular wire. Also note that the impedance of both circular wires and ground planes increase with increasing frequency and become quite significant at higher frequencies.

A commonly encountered situation interferencetechnology.com

design AWG# =10,D=2.59mm

AWG# =2,D=6.54mm

AWG# =22,D=.64mm

Freq.

= 1cm

= 10cm

 = 1m

 = 10m

= 1cm

= 1cm

= 10cm

 = 10cm

 = 1cm

 = 1cm

 = 1m

 = 10cm

10Hz 20Hz 30Hz 50Hz 70Hz

5.13µ 5.14µ 5.15µ 5.20µ 5.27µ

51.4µ 52.0µ 52.8µ 55.5µ 59.3µ

517µ 532µ 555µ 624µ 715µ

5.22m 5.50m 5.94m 7.16m 8.68m

32.7µ 32.7µ 32.8µ 32.8µ 32.8µ

327µ 328µ 328µ 329µ 330µ

3.28m 3.28m 3.28m 3.30m 3.33m

3.28m 3.28m 3.29m 33.2m 33.7m

529µ 529µ 530µ 530µ 530µ

5.29m 5.29m 5.30m 5.30m 5.30m

52.9m 53.0m 53.0m 5.30m 5.30m

529m 530m 530m 530m 530m

100Hz 200Hz 300Hz 500Hz 700Hz

5.41µ 6.20µ 7.32µ 10.1µ 13.2µ

56.7µ 99.5µ 137µ 219µ 303µ

877µ 1.51m 2.19m 3.59m 5.01m

11.2m 20.6m 30.4m 50.3m 70.2m

32.9µ 33.2µ 33.7µ 35.3µ 37.7µ

332µ 345µ 365µ 425µ 500µ

3.38m 3.67m 4.11m 6.28m 8.66m

34.6m 39.6m 46.9m 64.8m 84.8m

530µ 530µ 530µ 530µ 530µ

5.30m 5.30m 5.30m 5.32m 5.34m

53.0m 53.0m 53.0m 53.2m 53.4m

530m 530m 531m 533m 537m

1kHz 2kHz 3kHz 5kHz 7kHz

18.1µ 35.2µ 52.5µ 87.3µ 122µ

429µ 855µ 1.28µ 2.13µ 2.98µ

7.14m 14.2m 21.3m 35.6m 49.8m

100m 200m 300m 500m 700m

42.2µ 62.5µ 86.3µ 137µ 189µ

632m 1.13m 1.65m 2.72m 3.79m

632µ 1.13m 1.65m 2.72m 3.79m

8.91m 16.8m 25.0m 41.5m 58.1m

116m 225m 336m 559m 783m

531µ 536µ 545µ 571µ 609µ

53.9m 56.6m 60.9m 72.9m 87.9m

545m 589m 656m 835m 1.04

10Hz 20Hz 30Hz 50Hz 70Hz

174µ 348µ 523µ 871µ 1.22m

4.26µ 8.53µ 12.8µ 21.3µ 29.8µ

71.2m 142m 213m 356m 496m

1.00 2.00 3.00 5.00 7.00

268µ 533µ 799µ 1.33m 1.86m

5.41m 10.8m 16.2m 27.0m 37.8m

82.9m 165m 248m 414m 580m

1.11 2.23 3.35 5.58 7.82

681µ 1.00m 1.39m 2.20m 3.04m

8.89m 15.2m 22.0m 36.1m 50.2m

113m 207m 305m 504m 704m

1.39 2.63 3.91 6.48 9.06

100kHz 200kHz 300kHz 500kHz 700kHz

1.74m 3.48m 5.23m 8.71m 12.2m

42.6µ 85.3µ 128µ 213µ 298µ

712µ 1.42 2.13 3.56 4.98

10.0 20.0 30.0 50.0 70.0

2.66m 5.32m 7.98m 13.3m 18.6m

54.0 108 162 270 378

828 1.65 2.48 4.14 5.80

11.1 22.3 33.5 55.8 78.2

4.31m 8.59m 12.8m 21.4m 30.0m

71.6 142 214 357 500

1.00 2.00 3.01 5.01 7.02

12.9k 25.8k 38.7k 64.6k 90.4k

1MHz 2MHz 3MHz 5MHz 7MHz

17.4m 34.8m 52.3m 87.1m 122m

426µ 853µ 1.28 2.13 2.98

7.12 14.2 21.3 35.6 49.8

100 200 300 500 700

26.6m 53.2m 79.8m 133m 186m

540m 1.08 1.62 2.70 3.78

8.28 16.5 24.8 41.4 58.0

111k 223k 335k 558k 782k

42.8m 85.7m 128m 214m 300m

714m 1.42 2.14 3.57 5.00

10.0k 20.0k 30.1k 50.1k 70.2k

129 258 387 646 904

10MHz 20MHz 30MHz 50MHz 70MHz

174m 348m 523m 871m 1.22m

4.26 8.53 12.8 21.3 29.8

71.2 142 213 356 498

1.00k 2.00k 3.00k 5.00k 7.00k

266m 532m 798m 1.33 1.86

5.40 10.8 16.2 27.0 37.8

82.8 165 248 414 580

1.11k 2.23k 3.35k 5.58k 7.82k

428 857 1.28 2.14 3.00

7.14 14.2 21.4 35.7 50.0

100k 200k 301k 501k 702k

1.29k 2.58k 3.87k 6.46k 9.04k

100MHz 200MHz 300MHz 500MHz 700MHz 1GHz

1.74m 3.48m 5.23m 8.71m 12.2 17.4

42.6 85.3 128 213 298 426

712 1.42k 2.13k 3.56k 4.98k 7.12k

10.0k 20.0k 30.0k 50.0k 70.0k

2.66 5.32 7.98 13.3 18.6 26.6

54.0 108 162 270 378 540

828 1.65 2.48 4.14 5.80 8.28

11.1k 22.3k 33.5k 55.8k 78.2k

4.28 8.57 12.8 21.4 30.0 42.8

71.4 142 21.4 357 500 714

1.00k 2.00k 3.01k 5.01k 7.02k 10.0k

12.9k 25.8k 38.7k 64.6k 90.4k

µ = microhms m = milliohms  = ohms

*AWG = American Wire Gage D = Wire diameter in mm  = wire length in cm or m

Non-Valid Region for which  /4

Table 1. Impedance of Straight Circular Copper Wires.

is that of a ground cable (power or signal) running along in the proximity of a ground plane. This situation is illustrated in Figure 3 for equipment grounding. Figure 4 illustrates a representative circuit of this simple ground path. The effects of the resistive elements of the circuit will predominate at very low frequencies.

The relative influence of the reactive elements will increase at increasing frequencies. At some frequency, the magnitude of the inductive reactance (jωL) equals the magnitude of the capacitive reactance (1/jωC), and the circuit becomes resonant. The frequency of the primary (or first) resonance can be determined from:

allel or series resonant, respectively. At parallel resonance, the impedance seen looking into one end of the cable will be much higher than expected from R + jωL. (For good conductors, e.g., copper and aluminum, R « ωL; thus, jωL generally provides an accurate estimate of the impedance of a ground conductor at frequencies above a few hundred hertz). At parallel resonance:

(1) where L is the total cable inductance, and C is the net capacitance between the cable and the ground plane. At resonance, the impedance presented by the grounding path will either be high or low, depending on whether it is par-

where R(ac) is the cable resistance at the frequency of resonance. Then:

Zp = QωL

(2)

where Q, the quality factor, is defined as:

(3)

(4)

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71

design

G r o u n d i n g f o r t h e C o n t r o l o f E MI STEEL, COND-17, PERM-200

COPPER, COND-1, PERM-1 Freq.

t = .03

t = .1

t = .3

t=1

t=3

t = 10

t = .03

t = .1

t = .3

t=1

t=3

t = 10

10Hz 20Hz 30Hz 50Hz 70Hz

574µ 574µ 574µ 574µ 574µ

172µ 172µ 172µ 172µ 172µ

57.4µ 57.4µ 57.4µ 57.4µ 57.4µ

17.2µ 17.2µ 17.2µ 17.2µ 17.2µ

5.74µ 5.75µ 5.75µ 5.76µ 5.78µ

1.75µ 1.83µ 1.95µ 2.30µ 2.71µ

3.38m 3.38m 3.38m 3.38m 3.38m

1.01m 1.01m 1.01m 1.01m 1.01m

338µ 338µ 338µ 338µ 338µ

101µ 102µ 103µ 106µ 110µ

38.5µ 49.5µ 62.3µ 86.2µ 105µ

40.3µ 56.6µ 69.3µ 89.6µ 106µ

100Hz 200Hz 300Hz 500Hz 700Hz

574µ 574µ 574µ 574µ 574µ

172µ 172µ 172µ 172µ 172µ

57.4µ 57.4µ 57.4µ 57.4µ 57.4µ

17.2µ 17.2µ 17.2µ 17.2µ 17.2µ

5.82µ 6.04µ 6.38µ 7.36µ 8.55µ

3.35µ 5.16µ 6.43µ 8.27µ 9.77µ

3.38m 3.38m 3.38m 3.38m 3.38m

1.01m 1.01m 1.01m 1.01m 1.01m

338µ 340µ 342µ 350µ 362µ

118µ 157µ 199µ 275µ 335µ

127µ 197µ 219µ 283µ 335µ

126µ 179µ 219µ 283µ 335µ

1kHz 2kHz 3kHz 5kHz 7kHz

574µ 574µ 574µ 574µ 574µ

172µ 172µ 172µ 172µ 172µ

57.4µ 57.5µ 57.5µ 57.6µ 57.8µ

17.5µ 18.3µ 19.5µ 23.0µ 27.1µ

10.4µ 16.1µ 20.3µ 26.2µ 30.9µ

11.6µ 16.5µ 6.43µ 8.27µ 9.77µ

3.38m 3.38m 3.38m 3.38m 3.38m

1.01m 1.02m 1.03m 1.06m 1.10m

385µ 495µ 623µ 862µ 1.05m

403µ 566µ 693µ 896µ 1.06m

403µ 566µ 694µ 896µ 1.06m

403µ 566µ 694µ 896µ 1.06m

10Hz 20Hz 30Hz 50Hz 70Hz

574µ 574µ 574µ 574µ 574µ

172µ 172µ 172µ 173µ 173µ

58.2µ 60.4µ 63.8µ 73.6µ 85.5µ

33.5µ 51.6µ 64.3µ 82.7µ 97.7µ

36.9µ 52.2µ 63.9µ 82.6µ 97.7µ

36.9µ 52.2µ 63.9µ 82.6µ 97.7µ

3.38m 3.40m 3.42m 3.50m 3.62m

1.18m 1.57m 1.99m 2.75m 3.35m

1.27m 1.79m 2.19m 2.83m 3.35m

1.26m 1.79m 2.19m 2.83m 3.35m

1.26m 1.79m 2.19m 2.83m 3.35m

1.26m 1.79m 2.19m 2.83m 3.35m

100kHz 200kHz 300kHz 500kHz 700kHz

574µ 575µ 575µ 576µ 578µ

175µ 183µ 195µ 230µ 171µ

140µ 161µ 203µ 262µ 309µ

116µ 165µ 202µ 261µ 309µ

116µ 165µ 202µ 261µ 309µ

116µ 165µ 202µ 261µ 309µ

3.85m 4.95m 6.23m 8.62m 10.5m

4.03m 5.66m 6.93m 8.96m 10.6m

4.00m 5.66m 6.94m 8.96m 10.6m

4.00m 5.66m 6.94m 8.96m 10.6m

4.00m 5.66m 6.94m 8.96m 10.6m

4.00m 5.66m 6.94m 8.96m 10.6m

1MHz 2MHz 3MHz 5MHz 7MHz

582µ 604µ 638µ 736µ 855µ

335µ 516µ 643µ 827µ 977µ

369µ 522µ 639µ 826µ 977µ

369µ 522µ 639µ 826µ 977µ

369µ 522µ 639µ 826µ 977µ

369µ 522µ 639µ 826µ 977µ

12.7m 17.9m 21.9m 28.3m 33.5m

12.6m 17.9m 21.9m 28.3m 33.5m

12.6m 17.9m 21.9m 28.3m 33.5m

12.6m 17.9m 21.9m 28.3m 33.5m

12.6m 17.9m 21.9m 28.3m 33.5m

12.6m 17.9m 21.9m 28.3m 33.5m

10MHz 20MHz 30MHz 50MHz 70MHz

1.04m 1.61m 2.03m 2.62m 3.09m

1.16m 1.15m 2.02m 2.61m 3.09m

1.16m 1.15m 2.02m 2.61m 3.09m

1.16m 1.15m 2.02m 2.61m 3.09m

1.16m 1.15m 2.02m 2.61m 3.09m

1.16m 1.15m 2.02m 2.61m 3.09m

40.0m 56.6m 69.4m 89.6m 106m

40.0m 56.6m 69.4m 89.6m 106m

40.0m 56.6m 69.4m 89.6m 106m

40.0m 56.6m 69.4m 89.6m 106m

40.0m 56.6m 69.4m 89.6m 106m

40.0m 56.6m 69.4m 89.6m 106m

100MHz 200MHz 300MHz 500MHz 700MHz

3.69m 5.22m 6.39m 8.26m 9.77m

3.69m 5.22m 6.39m 8.26m 9.77m

3.69m 5.22m 6.39m 8.26m 9.77m

3.69m 5.22m 6.39m 8.26m 9.77m

3.69m 5.22m 6.39m 8.26m 9.77m

3.69m 5.22m 6.39m 8.26m 9.77m

126m 179m 219m 283m 335m

126m 179m 219m 283m 335m

126m 179m 219m 283m 335m

126m 179m 219m 283m 335m

126m 179m 219m 283m 335m

126m 179m 219m 283m 335m

1GHz 2GHz 3GHz 5GHz 7GHz 10GHz

11.6m 16.5m 20.2m 26.1m 30.9m 36.9m

11.6m 16.5m 20.2m 26.1m 30.9m 36.9m

11.6m 16.5m 20.2m 26.1m 30.9m 36.9m

11.6m 16.5m 20.2m 26.1m 30.9m 36.9m

11.6m 16.5m 20.2m 26.1m 30.9m 36.9m

11.6m 16.5m 20.2m 26.1m 30.9m 36.9m

400m 566m 694m 896m 1.06 1.26

400m 566m 694m 896m 1.06 1.26

400m 566m 694m 896m 1.06 1.26

400m 566m 694m 896m 1.06 1.26

400m 566m 694m 896m 1.06 1.26

400m 566m 694m 896m 1.06 1.26

*t is in units of mm µ = microhms m = milliohms  = ohms

NOTE: Do not use table at frequencies in MHz above 5/ m since the separation distance in meters,  m, of two grounded equipments will exceed 0.05 where error becomes significant.

Table 2. Metal Ground Plane Impedance in Ohms/Square.

Above the primary resonance, subsequent resonances (both parallel and series) will occur between the various possible combinations of inductances and capacitances (including parasitics) in the path.

Series resonances in the grounding circuit will also occur between the inductances of wire segments and one or more of the shunt capacitances.

The impedance (Zs) of a series resonant path is:

(5)

Therefore,

(6)

The series resonant impedance is thus determined by, and is equal to, the series ac resistance of the par72

interference technology

ticular inductance and capacitance in resonance. (At the higher ordered resonances, where the resonant frequency is established by wire segments and not the total path, the series impedance of the path to ground may be less than predicted from a consideration of the entire ground conductor length).

An understanding of the highfrequency behavior of a grounding conductor is simplified by viewing it as a transmission line. If the ground path is considered uniform along its run, the voltages and currents along the line can be described as a function of time and distance. If the resistance elements in Figure 4 are small relative to the inductances and capacitances, the grounding path has a characteristic impedance, Z0, equal to L/C where L and C are the per-unit length values of inductance and capacitance. The situation illustrated in Figure 3 is of particular

Figure 3. Idealized equipment grounding.

Figure 4. Equivalent circuit of a ground cable parallel to a ground plane.

interest in equipment grounding. The input impedance of the grounding path, i.e., the impedance to ground seen by the equipment case, is: Zin = jZ • tan 

(7)

where, ß=ωLC= the phase constant for the transmission line = the length of the path from the box to the short where ß is less than /2 radians, i.e., when the electrical path length is less than a quarter wavelength (/4), the input impedance of the short-circuited line is inductive with a value ranging from 0 (ß= 0) to ∞(ß= /2 radians).

As ß = increases beyond /2 radians in value, the impedance of the grounding path cycles alternately between its open- and short-circuit values.

Thus, from the vantage point of the device or component that is grounded, the impedance is analogous to that offered by a short-circuited transmission line. Where ß = /2, the impedance offered by the ground conductor behaves like a lossless parallel LC resonant circuit. Just below resonance, the impedance is inductive; just above resonance, it is capacitive; while at resonance, the impedance is real and quite high (infinite in the perfectly lossless case). Resonance occurs at values of  equal to integer multiples of quarter wavelengths, such as a half wavelength, three-quarter wavelength, etc.

emc Test & design guide 2011

Duff

design

Figure 5. Typical impedance vs. frequency behavior of a grounding conductor.

Figure 6. Photograph of the swept frequency behavior of a grounding strap.

Typical ground networks are complex circuits of Rs, Ls, and Cs with frequency-dependent properties including both parallel and series resonances. These resonances are important to the performance of a ground network. Resonance effects in a grounding path are illustrated in Figure 5. The relative effectiveness of a grounding conductor as a function of frequency is directly related to its impedance behavior (Figure 6).

It is evident from Figures 5 and 6 that, for maximum efficiency, ground conductor lengths should be a small portion

interferencetechnology.com

of the wavelength at the frequency of the signal of concern.

The most effective performance is obtained at frequencies well below the first resonance.

Antenna Characteristics Antenna effects are also related to circuit resonance behavior. Ground conductors will act as antennas to radiate or pick up potential interference energy, depending on their

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G r o u n d i n g f o r t h e C o n t r o l o f E MI

Figure 7. Common-mode impedance coupling between circuits.

Figure 8. Conductive coupling of extraneous noise into equipment interconnecting cables.

lengths relative to a wavelength, i.e., their efficiency. This fact permits a wavelength-to-physical-length ratio to be derived for ground conductors. The efficiency of a conductor as an antenna is related to its radiation resistance. Radiation resistance is a direct measure of the energy radiated from the antenna. A good measure of performance for a wire is a quarter-wave monopole, which has a radiation resistance of 36.5 ď —. An antenna that transmits or receives 10 percent or less than a monopole can be considered to be inefficient.

To be effective, a ground wire should be an inefficient antenna. A convenient criterion for a poor antenna, i.e., a

74 

interference technology

good ground wire, is that its length be ď Ź/10 or less. Thus, a recommended goal in the design of an effective grounding system is to maintain ground wires exposed to potentially interfering signals at lengths less than 1/10 of a wavelength of the interfering signal.

Ground-Related Interference Interference is any extraneous electrical or electromagnetic disturbance that tends to disrupt the reception of desired signals or produces undesirable responses in a circuit or system. Interference can be produced by both natural and man-made sources, either external or internal to the circuit. The correct operation of complex electronic equipment and facilities is inherently dependent upon the frequencies and amplitudes of both the signals utilized in the system and the potential interference emissions that are present. If the frequency of an undesired signal is within the operating frequency range of a circuit, the circuit may respond to the undesired signal (it may even happen out of band). The severity of the interference is a function of the amplitude and frequency of the undesired signal relative to that of the desired signal at the point of detection.

Ground-related interference often involves one of two basic coupling mechanisms. The first mechanism results from the fact that the signal circuits of electronic equipments share the ground with other circuits or equipments. This mechanism is called common-ground impedance coupling. Any shared impedance can provide a mechanism for interference coupling. Figure 7 illustrates the mechanism by which interference is coupled between culprit and victim circuits via the commonground impedance. In this case, the interference current, I, flowing through the common-ground impedance, Z, will produce an interfering signal voltage, Vc, in the victim circuit. It should be emphasized that the interference current flowing in the common impedance may be either a current that is related to the normal operation of the culprit circuit or an intermittent current that occurs due to abnormal events (lightning, power faults, load changes, power line transients, etc.).

emc Test & design guide 2011

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design

Figure 10. Grounding hierarchy.

Even if the equipment pairs do not use the signal ground as the signal return, the signal ground can still be the cause of coupling between them. Figure 8 illustrates the effect of a stray current, IR, flowing in the signal ground. The cur-

Figure 9. Common-mode radiation into and from ground loops.

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G r o u n d i n g f o r t h e C o n t r o l o f E MI

rent IR may be the result of the direct coupling of another equipment pair to the signal ground. It may be the result of external coupling to the signal ground, or induced in the ground by an incident field. In either case, IR produces a voltage V N in the ground impedance ZR. This voltage produces a current in the interconnecting loop, which in turn develops a voltage across ZL in Equipment B. Thus, it is evident that interference can conductively couple through the signal ground to all circuits and equipment connected across the non-zero impedance elements of that ground.

The second EMI coupling mechanism involving ground is a radiation mechanism whereby the ground loop, as shown in Figure 9, acts as a receiving or transmitting antenna. For this EMI coupling mechanism, the characteristics of the ground (resistance or impedance) do not play an important role, because the induced EMI voltage (for the susceptibility case) or the emitted EMI field (for the emission case) is mainly a function of the EMI driving function (field strength, voltage, or current), the geometry and dimensions of the ground loop, and the frequency of the EMI signal. It should be noted that both the conducted and radiated EMI coupling mechanisms identified above involve a “ground loop.” However, it should be recognized that ground loop EMI problems can exist without a physical connection to ground. In particular, at RF frequencies, distributed capacitance to ground can create a ground loop condition even though circuits or equipments are floated with respect to ground.

Also, it should be noted that, for both of the EMI coupling mechanisms involving the ground loop, the EMI currents in the signal lead and the return are flowing in the same direction. This EMI condition (where the currents in the signal lead and the return are in phase) is referred to as common-mode EMI. The EMI control techniques that will be effective for ground loop problems are those that either reduce the coupling of EMI into the ground loop or provide suppression of the common-mode EMI that is coupled into the ground loop.

Figure 11. Single-point or star grounding arrangement.

Figure 12. Degeneration of single-point ground by interconnecting cables and parasitic capacitance.

Circuit, Equipment, and System Grounding In the previous section, EMI coupling mechanisms resulting from circuit, equipment, and system grounding were identified and discussed.

At this point, it should be obvious that grounding is very important from the standpoint of minimizing and controlling EMI. However, grounding is one of the least understood and most significant culprits in many system-level EMI problems. The grounding scheme of a system must perform the following functions: • A nalog, low-level, and low-frequency circuits must have noise-free dedicated returns. Due to the low frequencies involved, wires are generally used (more or less dictating a single-point or star ground system).

• A nalog high-frequency circuits {radio, video, etc.} must have low impedance, noise-free return circuits, generally in form of planes or coaxial cables.

Figure 13. Multipoint grounding system.

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emc Test & design guide 2011

Duff

design Daisy Chaining (Poor)

Heavier Ground Path (Better)

Ground Plane (Better Still)

or:

Parallel Ground Wires (Better)

Ground Grid (Better Still)

Figure 14. Means of decreasing common-impedance coupling by decreasing ground path impedance. From the bad practice of daisychain (top), the improvement evolves toward a plane (left) or a grid (right).

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Figure 15. Float circuits or equipments.

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G r o u n d i n g f o r t h e C o n t r o l o f E MI

Figure 16. Capacitive grounding.

Figure 19. Common-mode isolation transformer.

Figure 17. Inductive grounding..

Figure 18. Common-mode chokes.

• Returns of logic circuits, especially high-speed logic, must have low impedances over the whole bandwidth (dictated by the fastest rise times), since power and signal returns share the same paths.

• Returns of powerful loads (solenoids, motors, lamps, etc.) should be distinct from any of the above, even though they may end up in the same terminal of the power supply regulator.

• Return paths to chassis of cable shields, transformer shields, filters, etc. must not interfere with functional returns.

• W hen the electrical reference is distinct from the chassis ground, provision and accessibility must exist to connect and disconnect one from the other.

• More generally, for signals that communicate within the equipment or between parts of a system, the grounding scheme must provide a common reference with minimum ground shift (unless these links are balanced, optically isolated, etc.). Minimum ground shift means that the common-mode voltage must stay below the sensitivity threshold of the most susceptible device in the link.

All the above constraints can be accommodated if their functional returns and protective grounds are integrated 78

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Figure 20. Use of optical isolation to combat common-mode impedance.

into a grounding system hierarchy as shown in Figure 10.

The application of this concept is the subject of the following discussion.

Modern electronic systems seldom have only one ground.

To mitigate interference, such as due to common-mode impedance coupling, as many separate grounds as possible are used. Separate grounds in each subsystem for structural grounds, signal grounds, shield grounds, and primary and secondary power grounds are desirable if economically and logistically practical. These individual grounds from each subsystem are finally connected by the shortest route back to the system ground point, where they form an overall system potential reference. This method is known as a single-point ground and is illustrated in Figure 11.

Single-Point Grounding Scheme The single-point or star type of grounding scheme shown in the figure avoids problems of common-mode impedance coupling discussed in the previous section. The only com

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design

Figure 23. Single-point signal ground.

Figure 21. Balanced configuration with respect to common-mode voltage.

Figure 22. Floating Signal Ground.

mon path is in the earth ground (for earth-based structures), but this usually consists of a substantial conductor of very-low impedance. Thus, as long as no or low ground currents flow in any low-impedance common paths, all subsystems or equipments are maintained at essentially the same reference potential.

The problem of implementing the above single-point grounding scheme comes about when (1) interconnecting cables are used, especially ones having cable shields that have lengths on the order of 1/20 of a wavelength or greater, and (2) parasitic capacitance exists between subsystem or equipment housings or between subsystems and the grounds of other subsystems. This situation is illustrated in Figure 12.

Here, cable shields connect some of the subsystems together so that more than one grounding path from a particular subsystem to the ground point exists. Unless precautions are taken, common-impedance ground currents could flow. At high frequencies, the parasitic capacitive reactance represents low-impedance paths, and the bond inductance of a subsystem-to-ground point results in higher impedances.

Thus, again, common-mode currents may flow or unequal potentials may develop between subsystems. interferencetechnology.com

Figure 24. Single-point ground bus system using a common bus.

Multipoint Grounding Scheme Rather than have an uncontrolled situation as shown in Figure 12, the other grounding alternative is multipoint grounding as illustrated in Figure 13. For the example shown in Figure 13, each equipment or subsystem is bonded as directly as possible to a common low-impedance ground plane to form a homogeneous, low-impedance path. Thus, common-mode currents and other EMI problems will be minimized. The ground plane then is earthed for safety purposes.

Selection of a Grounding Scheme The facts are that a single-point grounding scheme operates better at low frequencies, and a multipoint ground behaves best at high frequencies. If the overall system, for example, is a network of audio equipment, with many low-level sensors and control circuits behaving as broadband transient noise sources, then the high-frequency performance is irrelevant, since no receptor responds above audio frequency.

For this situation, a single-point ground would be effec

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point grounding (for hybrid grounds), if used, would be to avoid low-frequency ground current loops a n d /o r c o m m o n mode impedance coupling.

I n s u m m a r y, many system-level EMI problems can be avoided by paying careful attention to Figure 25. Multiple-point ground configuration. the grounding scheme used. Commonmode, common-ground impedance problems may be reduced by applicative. Conversely, if the overall system tion of one or more of the following were a receiver complex of 30 to 1,000 techniques.

MHz tuners, amplifiers, and displays, • Eliminate common impedance then low-level, low-frequency perfor- by using a single point ground (Figure mance is irrelevant. Here, multipoint 11) if possible. This configuration is grounding applies, and interconnect- usually optimal for power frequencies ing coaxial cables should be used. and signal frequencies below 300 kHz. The above comparison of audio • Separate and isolate grounds on versus VHF/UHF systems makes clear the basis of signal type, level, and the selection of the correct approach. frequency as illustrated in Figure 10.

The problem then narrows down • Minimize ground impedance as to one of defining where low- and illustrated in Figure 14 by ushigh-frequency crossover exists for ing ground bus, ground plane, or any given subsystem or equipment. ground grid.

The answer here in part involves the • Float circuits or equipments if highest significant operating frepractical from a safety standpoint quency of low-level circuits relative as illustrated in Figure 15. The efto the physical distance between the fectiveness of floating circuits or farthest located equipments. equipments depends on their physiThe determination of the crossover cal isolation from other conductors. frequency region involves considerIn large facilities, it is difficult to ation of (1) magnetic versus electric achieve a floating system. field coupling problems and (2) • Use an inductor or capacitor in ground-plane impedance problems the ground connection to provide due to separation. Hybrid single and high- or low-frequency isolation, multipoint grounding systems are respectively, as illustrated in Figures often the best approach for crossover 16 and 17. region applications.

• Use filters or ferrites in ground loops When printed circuits and ICs are to limit common-mode currents or used, network proximity is considerprovide a common-mode voltage ably closer. Thus, multipoint grounddrop. ing is more economical and practical • Use a common-mode choke as ilto produce per card, wafer, or chip. lustrated in Figure 18 or a common Interconnection of these components mode isolation transformer as ilthrough wafer risers, motherboards, lustrated in Figure 19 to suppress etc. should use a grounding scheme ground-loop EMI. These devices following the illustrations of previous may provide on the order of 60 dB of paragraphs. common-mode rejection at frequenThis will likely still represent cies up to several hundred kilohertz. a multipoint or hybrid ground- • Use optical isolators and/or fiber ing approach in which any singleoptics to block common-mode EMI 80

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effects as illustrated in Figure 20.

Optical isolators provide a high degree of common-mode rejection at frequencies up to and including the HF band (i.e., 3 to 30 MHz). Optical isolators are usually limited to digital applications (they are not applicable to low-level analog circuits).

• Use balanced circuits to minimize effects of common-mode EMI in the ground loop as illustrated in Figure 21. With a perfectly balanced circuit, the currents flowing in the two parts of the circuit will produce equal and opposite voltages across the load, so the resulting voltage across the load is zero. Balanced circuits can provide significant (greater than 20 dB) commonmode reduction for low-frequency conditions. However, at higher frequencies (above 30 MHz), other effects start to predominate, and the effectiveness of balanced circuits diminishes.

Common-mode radiated EMI effects resulting from emissions that are radiated or picked up by a ground loop may be reduced by the application of one or more of the following techniques: • M i n i m i ze t he com mon-mode ground loop area by routing interconnecting wires or cable close to the ground.

• Reduce the common-mode ground loop currents by floating circuits or equipments; using optical isolators; or inserting common-mode filters, chokes, or isolation transformers.

• Use balanced circuits or balanced drivers and receivers.

Ground System Configurations The ground system for a collection of circuits within a system or facility can assume any one of several different configurations. Each of these configurations tends to be optimal under certain conditions and may contribute to EMI problems under other conditions.

In general, the ground configurations will involve either a floating ground, a single point ground, a multipoint ground, or some hybrid combination of these.

A floating ground configuration is interferencetechnology.com

design illustrated in Figure 22. This type of signal ground system is electrically isolated from the ground and other conductive objects. Hence, noise currents present in the ground system will not be conductively coupled to the signal circuits. The floating ground system concept is also employed in equipment design to isolate signal returns from equipment cabinets and thus prevent unwanted currents in cabinets from coupling directly to signal circuits.

Effectiveness of floating ground systems depends on their true isolation from other nearby conductors; floating ground systems must really float. In large facilities, it is often difficult to achieve and maintain an effective floating system. Such a floating system is most practical if a few circuits or a few pieces of equipment are involved and power is applied from either batteries or dc-to-dc converters.

A single-point ground for an equipment complex is illustrated in Figure 23. With this configuration, the signal circuits are referenced to a single point, and this single point is then connected to the facility ground.

The ideal single-point signal ground network is one in which separate ground conductors extend from one point on the facility ground to the return side of each of the numerous circuits located throughout a facility. This type of ground network requires an extremely large number of conductors and is not generally economically feasible. In lieu of the ideal, various degrees of approximation to single point grounding are employed.

The configuration illustrated in Figure 24 represents a ground bus arrangement that is often used to provide an approximation to the single-point grounding concept. The ground bus system illustrated in Figure 24 assumes the form of a tree. Within each system, the individual subsystems are single-point grounded. Each of the system ground points is then connected to the tree ground bus with a single insulated conductor.

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300 kHz. The multiple-point ground illustrated in Figure 25 is the third configuration frequently used for signal ground networks. This configuration establishes many conductive paths to various electronic systems or subsystems within a facility. Within each subsystem, circuits and networks have multiple connections to this ground network. Thus, in a facility, numerous parallel paths exist between any two points in the multiple point ground network.

Multiple-point grounding frequently simplifies circuit construction inside complex equipment. It permits equipment employing coaxial cables to be interfaced more easily, since the outer conductor of the coaxial cable does not have to be floated relative to the equipment cabinet or enclosure.

However, multiple-point grounding suffers from an important disadvantage. Power currents and other highamplitude, low-frequency currents flowing through the facility ground system can conductively couple into signal circuits to create intolerable interference in susceptible lowfrequency circuits. Also, multiple ground loops are created, and this makes it more difficult to control radiated emission or susceptibility resulting from the common-mode ground loop effects. In addition, for multiple-point grounding to be effective, all ground conductors between the separate points must be less than 0.1 wavelength of the interference signal. Otherwise, common-ground impedance and ground radiated effects will become significant. In general, multiplepoint grounding configurations tend to be optimum at higher frequencies (i.e., above 30 MHz).

To illustrate one form of a hybrid-ground system, Figure 26 shows a 19-in cabinet rack containing five separate sliding drawers. Each drawer contains a portion of the system (top to bottom): (1) RF and IF preamp circuitry for reception of microwave signals, (2) IF and video signal amplifiers, (3) display drivers, displays, and control circuits, (4) low-level audio circuits and recorders for documenting sensitive multichannel, hard-line telemetry sensor outputs, and (5) secondary and regulated power supplies. The hybrid aspect results from: • The RF and IF video drawers are similar. Here, unitlevel boxes or stages (interconnecting coaxial cables are grounded at both ends) are multipoint grounded to the drawer-chassis ground plane. The chassis is then grounded to the dagger pin, chassis ground bus as suggested in Figure 27. The power ground to these drawers, on the other hand, is using a single-point ground from its bus in a manner identical to the audio drawer.

• The chassis or signal ground and power ground busses each constitute a multipoint grounding scheme to the drawer level. The individual ground busses are singlepoint grounded at the bottom ground distribution block. This avoids circulating common-mode current between chassis or signal ground and power grounds, since power ground current can vary due to transient surges in certain modes of equipment operation.

• Interconnecting cables between different drawer levels are run separately, and their shields, when used, are treated

Figure 26. Grounding arrangement used in cabinet racks.

The single-point ground accomplishes each of the three functions of signal circuit grounding. That is, a signal reference is established in each unit or piece of equipment, and these individual references are connected together. These, in turn, are connected to the facility ground at least at one point, which provides fault protection for the circuits and provides control over static charge buildup.

An important advantage of the single-point configuration is that it helps control conductively coupled interference. As illustrated in Figure 23, closed paths for noise currents in the signal ground network are avoided, and the interference currents, or voltages in the facility ground system, are not conductively coupled into the signal circuits via the signal ground network. Therefore, the single-point signal ground network minimizes the effects of any noise currents that may be flowing in the facility ground.

In a large installation, a major disadvantage of a singlepoint ground configuration is the requirement for long conductors. In addition to being expensive, long conductors prevent realization of a satisfactory reference for higher frequencies because of large self-impedances. Furthermore, because of stray capacitance between conductors, single point grounding essentially ceases to exist as the signal frequency is increased. In general, for typical equipments, systems, or facilities, single-point grounds tend to be optimum for frequencies below approximately 82

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design provide maximum EMI protection. A detailed discussion of specific grounding considerations associated with these EMI control techniques or devices is beyond the scope of this book. However, it is important to emphasize the importance of grounding on the performance of these techniques or devices, and details may be found in the references.

Suggested Readings • [1] Morrison, Ralph, and W. H. Lewis, Grounding and Shielding in Facilities, Hoboken, NJ: John Wiley & Sons, 1990.

• [2] Morrison, Ralph, Grounding and Shielding Techniques in Instrumentation, 3rd ed., Hoboken, NJ: John Wiley & Sons, 1990.

• [3] Denny, Hugh W., Grounding for the Control of EMI, Gainesville, VA, Interference Control Technologies, Inc. • [4] Grounding, Bonding and Shielding for Electronic Equipment and Facilities, MIL-HDBK-419.

Dr. William G. Duff is the president of SEMTAS. Previously, he was the chief technology officer of the Advanced Technology Group of SENTEL. Prior to working for SENTEL, he worked for Atlantic Research and taught courses on electromagnetic interference and electromagnetic compatibility. He is internationally recognized as a leader in the development of engineering technology for achieving EMC in communication and electronic systems. He has 42 years of experience in EMI/EMC analysis, design, test and problem solving for a wide variety of communication and electronic systems. n

Figure 27. Block diagram detail of hybrid grounding arrangement.

in the same grounding manner as at the drawer level.

• The audio and display drawers shown in Figure 27 use single-point grounding throughout for both their unit-level boxes (interconnecting twisted cable is grounded at one end to its unit) and power leads.

Cable and unit shields are all grounded together at the common dagger pin bus. Similarly, the outgoing power leads and twisted returns are separately bonded on their dagger pin busses.

To review the above scheme, the following is observed: • The audio and display drawers have ground runs of about 0.6 m and an upper frequency of operation of about 1 MHz (driver and sweep circuits). Thus, single-point grounding to the strike pins is indicated.

• The RF and IF drawers process UHF and 30 MHz signals over a distance of a meter so that multipoint grounding is indicated.

• The regulated power supplies furnish equipment units having transient surge demands. The longest length is about 1.5 m, and significant transient frequency components may extend up in the HF region.

Here, hybrid grounding is indicated: single-point within a drawer and multipoint from the power bus to all drawers.

EMI Control Devices and Techniques The performance of some EMI control techniques or devices may be significantly influenced by grounding.

In particular, cable shields; isolation transformers; EMI filters; ESD, lightning, and EMF protection techniques; and Faraday shields must be properly grounded so as to interferencetechnology.com

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A C o m pa r i s o n b e t w e e n G e l at i n o u s a n d T ac k y C o at e d T y p e P ac k ag i n g C a r r i e r s

A Comparison between Gelatinous and Tacky Coated Type Packaging Carriers For Manual Pick & Placement of Class 0 ESD Sensitive Devices within the ESD Protected Area (EPA)

junction with tweezers for manual pick and placement) were selected for test and evaluation.

Robert J. Vermillion RMV Technology Group, LLC NASA-Ames Research Center Moffett Field, California USA

Doug Smith DC Smith Consultants Los Gatos, California, USA

F

or years, semiconductor and aerospace engineers have fielded questions regarding the suitability of using gelatinous and tacky coated packaging materials for the distribution, storage, and sale of ESD sensitive devices. Since this type of packaging is often utilized for ESD sensitive devices on an ANSI/ESD S4.1-2006 ESD work surface without ionization, the question arises: Does the practice of anchoring components without requiring specially designed packaging or ionization constitute a compliant method in protecting Ultrasensitive Class 0 ESD devices?1 The author’s intent is to analyze gelatinous and tacky coated technologies for compliance within a static controlled environment or ESD Protected Area (EPA). Two product carrier t ypes, a cross-link gelatinous polymer insert (Figure 1) and a coated polymer insert with static dissipative properties Figure 1. A cross-link gelatinous polymer insert. (each used in con84

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Background To gain a better understanding of potential risks associated with the use of inadequate packaging within an ANSI/ESD S4.1-2006 or MIL-PRF-87893B-1997 protective ESD work station, one needs only to compare today’s technology miniaturization to 1969 when Apollo 11 landed on the moon. In May 2011, Astronaut Col. Buzz Aldrin, Ph.D. stated that a hand held smart phone has more processing power than NASA’s Apollo 11 computer. In 1971, the Intel 4004 microprocessor was 2300 transistors equivalent.

Now, according to Processor News, Intel’s CPU breaks the 2 billion transistor barrier with the Tukwila (Reference Illustration 1).

As technology has progressed from ferrite cores, to individual transistors, to billions of transistors, the ESD sensitivity of these devices has increased exponentially. The relative robustness of devices with ESD sensitivities of 1000 volts in the early 80s has been replaced with device threshold below 50 volts today. The disk drive sector’s GMR, (giant magnetoresistive), PMR (perpendicular magnetic recording), TMR (tunneling magnetoresistive), and HAMR (heat assisted magnetic recording) generally identified as EAMR (Energy Assisted Magnetic Recording) heads are known for ESD sensitivity at <5 volts for the past five years or more. Today HBM sensitivity is 1. <50 volts emc Test & design guide 2011

electrostatic discharge

A C o m pa r i s o n b e t w e e n G e l at i n o u s a n d T ac k y C o at e d T y p e P ac k ag i n g C a r r i e r s

Figure 2. Product A undergoing Surface Resistance testing.

Reference illustration 1. According to Processor News, Intel’s CPU breaks the 2 billion transistor barrier with the Tukwila.

about 1 volt. Increasing the necessity of protecting devices from ESD events at these low levels will ensure both yield and reliability.

Because of increased device sensitivity, in-process packaging and handling materials should be capable of offering the aerospace & defense, semiconductor, medical device, disk drive and automotive community protection from electrostatic discharge by meeting the requirements called out in ANSI/ESD S541-2008. Section 7.0 - Classification of ESD Packaging Material Properties that states: Materials and packages useful in preventing damage to sensitive electronic devices exhibit certain properties that include: • Low Charging (antistatic) • Resistance:

-Conductive

-Dissipative

-Insulative • Shielding:

-Electrostatic Discharge

-Electric-field

Figure 3. Volume Resistance testing for Product B.

of the packages: 1. Surface Resistance (ANSI/ESD STM11.11) at 12%+/3%RH 2. Volume Resistance (ANSI/ESD STM11.12) at 12%+/3%RH 3. Electrostatic Decay; Gelatinous/Tacky inserts to Ground [MIL-STD-3010B (Modified),12%+/-3%RH] 4. Faraday Cup testing per ESD adv.11.2 at 12%+/-3%RH 5. Peak Voltages of Products A and B inserts at 12%+/3%RH after Charge and Grounding 6. Contact Discharge of Tweezers making intimate Contact with an ESD Sensitive Device after 1kV charging at 30%RH. a. Current Probe

i. with ionization

ii. without ionization

Methodology and Test Results As previously stated, two products were evaluated for suitability in an EPA Class Zero ESD workstation. Product A is a cross-linked gelatinous polymer package insert. According to the supplier claims, Product B is a tacky static dissipative coating property independent of the conductive surface below. Both the gelatinous polymer and tacky surface coating, hold devices in place either upside down or horizontal to a work station and require minimal effort for physical removal of the devices from the packaging.

In this article, the battery of ESD tests represents a snapshot of what is required for compliance to a formalized materials qualification process. The following testing methods were utilized to determine the ESD safe performance 86

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Surface and Volume Resistance versus Relative Humidity (RH) It is a misconception to assume that ESD testing at low and high relative humidities will produce similar measurements. Arguably, this may be true for humidity independent technologies, but materials that rely upon moisture to facilitate electrical conductivity such as antistatic polymers may produce significantly different readings at 50% RH in comparison to ESD testing at 12% RH. Many organizations maintain 30%RH to 70%RH within an EPA. In accordance with ANSI/ESD STM11.11-2006 and ANSI/ESD STM11.12-2007, Products A and B were preconditioned at 12% +/-3% RH and 730F +/-50F for 48 hours prior

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A C o m pa r i s o n b e t w e e n G e l at i n o u s a n d T ac k y C o at e d T y p e P ac k ag i n g C a r r i e r s

Product A Base Outside

Product A Lid Outside

Product A Inside Lid

Product A Inside Polymer

Number

Resistance Ω

Constant V

Number

Resistance Ω

Constant V

Number

Resistance Ω

Constant V

Number

Resistance Ω

Constant V

1

1.0E+04

10v

1

1.1E+04

10v

1

2.8E+04

10v

1

4.7E+12

100v

2

2.5E+04

10v

2

3.1E+04

10v

2

4.2E+04

10v

2

1.5E+12

100v

3

4.0E+04

10v

3

4.1E+04

10v

3

3.2E+04

10v

3

3.2E+12

100v

4

4.3E+04

10v

4

4.8E+04

10v

4

5.2E+04

10v

4

4.6E+12

100v

5

7.4E+04

10v

5

1.1E+04

10v

5

5.5E+04

10v

5

2.2E+12

100v

6

8.1E+04

10v

6

4.3E+04

10v

6

6.1E+04

10v

6

2.6E+12

100v

Average

4.6E+04

Average

3.1E+04

Average

4.5E+04

Average

3.2E+12

Median

4.2E+04

Median

3.6E+04

Median

4.7E+04

Median

2.9E+12

Minimum

1.0E+04

Minimum

1.1E+04

Minimum

2.8E+04

Minimum

1.5E+12

Maximum

8.1E+04

Maximum

4.8E+04

Maximum

6.1E+04

Maximum

4.7E+12

St. Dev.

2.8E+04

St. Dev.

1.7E+04

St. Dev.

1.3E+04

St. Dev.

1.3E+12

PASSED

Product B Lid Outside

PASSED

Product B Base Outside

PASSED

Product B Inside Lid

FAILED

Product B Inside Polymer

Number

Resistance Ω

Constant V

Number

Resistance Ω

Constant V

Number

Resistance Ω

Constant V

Number

Resistance Ω

Constant V

1

3.2E+02

2.5v

1

8.4E+02

2.5v

1

2.9E+02

2.5v

1

7.3E+05

10v

2

4.4E+02

2.5v

2

5.4E+02

2.5v

2

2.4E+02

2.5v

2

6.5E+05

10v

3

3.3E+02

2.5v

3

3.3E+02

2.5v

3

2.6E+02

2.5v

3

5.4E+05

10v

4

4.4E+02

2.5v

4

7.3E+01

2.5v

4

6.8E+01

2.5v

4

4.5E+05

10v

5

3.3E+02

2.5v

5

1.8E+02

2.5v

5

3.7E+02

2.5v

5

2.0E+05

10v

6

2.5E+02

2.5v

6

3.7E+02

2.5v

6

4.7E+02

2.5v

6

1.4E+05

10v

Average

3.5E+02

Average

3.9E+02

Average

2.8E+02

Average

4.5E+05

Median

3.3E+02

Median

3.5E+02

Median

2.7E+02

Median

5.0E+05

Minimum

2.5E+02

Minimum

7.3E+01

Minimum

6.8E+01

Minimum

1.4E+05

Maximum

4.4E+02

Maximum

8.4E+02

Maximum

4.7E+02

Maximum

7.3E+05

St. Dev.

7.4E+01

St. Dev.

2.7E+02

St. Dev.

1.4E+02

St. Dev.

2.4E+05

PASSED

PASSED

PASSED

PASSED

Table 1. Surface Resistance: 12.1%RH, 73.2 0F after 48 Hours of preconditioning.

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V e r m i l l i o n, S m i t h

Product B

Product A

Table 2. The gelatinous-like substrate of Product A measured above the threshold of <1.0 x 1011 ohms for an average of 3.2 x 1012 ohms (failed); Product B findings, however, were in the static dissipative range for an average of 4.5 x 105 ohms (passed).

to testing. Figure 2 illustrates Product A undergoing Surface Resistance testing; Figure 3 illustrates Volume Resistance testing for Product B. Products A and B surface resistance measurements are benchmarked in Table 1.

For Product A, the exterior carbon loaded rigid plastic cases measured in the lower static dissipative range. Product B produced conductive readings (Table 1) for said cases. Both cases are suitable for use in an EPA. Since the components make intimate contact with Products A and B substrates, a carbon case would not represent a CDM hazard. As illustrated in Table 2, the gelatinous-like substrate of Product

Number

Resistance Ω

Constant V

Number

Resistance Ω

Constant V

1

1.7E+12

100v

1

1.3E+06

100v

2

6.2E+12

100v

2

9.6E+05

100v

3

1.4E+12

100v

3

1.2E+06

100v

4

2.4E+12

100v

4

5.9E+05

10v

5

1.7E+12

100v

5

8.2E+06

100v

6

1.9E+12

100v

6

6.4E+05

10v

Average

2.6E+12

Average

2.2E+06

Median

1.8E+12

Median

1.1E+06

Minimum

1.4E+12

Minimum

5.9E+05

Maximum

6.2E+12

Maximum

8.2E+06

St. Dev.

1.8E+12

St. Dev.

3.0E+06

FAILED

PASSED

Table 3. Volume Resistance: 12.1%RH, 73.2 0F after 48 hours of preconditioning.

The Interference Technology website organizes information in the way you need it.

Are you having an EMI testing problem and need advice or are you an EMI testing specialist and can help others by sharing your knowledge?

Look no further than our EMI Testing Forum where you can post your comments and questions as well as help peers by answering posts.

Check the forum regularly, and stay informed!

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Figure 4a. For Product A, the test was stopped (left) after 3 seconds.

Product B (right), however, facilitated electrostatic decay through the grounded polymer insert and carbon case on top of a charge plate.

Table 4

A measured above the threshold of <1.0 x 1011 ohms for an average or 3.2 x 1012 ohms (failed); Product B findings, however, were in the static dissipative range for an average of 4.5 x 105 ohms (passed).

Volume Resistance testing is important as it represents a packageâ&#x20AC;&#x2122;s ability to maintain continuity when placed atop a grounded work station. In Product A, a charged gelatinous surface (despite being grounded) could represent an ESD hazard when stainless steel tweezers make contact with ESD sensitive devices.

Product A Volume Resistance (Table 3) average measured insulative at 2.6 x 1012 ohms (failed). Product B, however, measured static dissipative at 2.2 x 10 6 ohms (passed).

Figure 4b. Even after grounding for 5 seconds, the Product A gelatinous insert substrate did not bleed off charge.

Electrostatic Decay per â&#x20AC;&#x192; Mil-STD-3010B-2008 (Modified)

3010B specifies that the charged object at +/- 5000 volts should drain the voltage to +/- 500 volts or lower. For several years, a common voltage range of +/-1000 volts to +/-100 volts has been utilized. A decay time of less than 2.0 seconds

Electrostatic Decay This test method measures the rate of decay of a charged isolated object to 10 percent of its original value. Mil-STD-

Figure 5. The packages were removed from the plate, grounded for a period of 5.0 seconds and allowed to free fall into a Faraday Cup.

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V e r m i l l i o n, S m i t h Product A Insert to Plate

Product A Insert to Plate

Product B Insert to Plate

Product A Insert to Plate

Number

Seconds

Start V

Number

Seconds

Start V

Number

Seconds

Start V

Number

Seconds

Start V

1

3.0

1000v

1

3.0

-1000v

1

0.01

1000v

1

0.01

-1000v

2

3.0

1000v

2

3.0

-1000v

2

0.06

1000v

2

0.01

-1000v

3

3.0

1000v

3

3.0

-1000v

3

0.01

1000v

3

0.01

-1000v

4

3.0

1000v

4

3.0

-1000v

4

0.06

1000v

4

0.01

-1000v

5

3.0

1000v

5

3.0

-1000v

5

0.02

1000v

5

0.03

-1000v

6

3.0

1000v

6

3.0

-1000v

6

0.04

1000v

6

0.01

-1000v

Average

3.0

Average

3.0

Average

0.03

Average

0.01

Median

3.0

Median

3.0

Median

0.03

Median

0.01

Minimum

3.0

Minimum

3.0

Minimum

0.01

Minimum

0.01

Maximum

3.0

Maximum

3.0

Maximum

0.06

Maximum

0.03

St. Dev.

0.0

St. Dev.

0.0

St. Dev.

0.02

St. Dev.

0.01

FAILED

FAILED

PASSED

PASSED

Table 5. Static Decay: +/-1kV to +/-100 volts in <2.0 seconds.

Electrostatic Decay

The perfect pair Electrostatic Discharge ESD Simulator

Table 6. Product A overlaps in Table 6 and is above the limit of <2.0 seconds. Product B, however, passed.

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is called out in MIL-PRF-81705E and the former EIA-541 as passing. This test represents a material's ability to dissipate induced voltage with proper grounding. Decay tests have difficulty with materials of complex construction such as ESD convoluted foams, vacuum-formed polymers and small items that could fall below the measuring range of the testing equipmentâ&#x20AC;&#x2122;s fixturing.

For Product A, the test was stopped (see Figure 4a, left) after 3 seconds. Product B (see Figure 4a, right), however, facilitated electrostatic decay through the grounded polymer insert and carbon case on top of a charge plate.

Even after grounding for 5 seconds, the Product A gelatinous insert substrate did not bleed off charge (see Figure interferencetechnology.com

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electrostatic discharge

A C o m pa r i s o n b e t w e e n G e l at i n o u s a n d T ac k y C o at e d T y p e P ac k ag i n g C a r r i e r s

Product B

Product A

Number

nC

Start V

Number

nC

Start V

1

9.18

1000v

1

0.01

1000v

2

4.68

1000v

2

0.06

1000v

3

1.89

1000v

3

0.34

1000v

4

5.09

1000v

4

0.01

1000v

5

-1.45

1000v

5

0.01

1000v

6

0.13

1000v

6

0.13

1000v

Average

3.25

FAILED

Average

0.09

PASSED

Median

3.29

Median

0.04

Minimum

-1.45

Minimum

0.01

Maximum

9.18

Maximum

0.34

St. Dev.

3.85

St. Dev.

0.13

Table 8. Faraday Cup results.

surement device as illustrated in Figure 6. It is important to test for hot spots since an ESD sensitive device could be placed over this area and damaged by tweezer removal. If the overall surface measures <50 volts and one spot peaks out at 200 volts, this could represent a potential hazard to a 100 volt ESD sensitive device with tweezer contact. Product A peak voltage surpassed the range of the non-contact voltage system at -1023.5 volts. Product B peaked at -30 volts.

Contact Discharge Measurements with and without Ionization using Tweezers Conducting Contact Discharge Measurements “with and without” Ionization Both Products A (glossy looking insert) and B (satin appearing insert) were placed on a charge plate with a US quarter atop the packaging inserts. Under ionization, Product A was neutralized to remove charge. A 6” x 6” 20pF charge plate was then charged to 1000 volts. A grounded person makes intimate contact with the quarter and then grounds the charge plate. This simulates a grounded operator at an ANSI/ ESD S4.1 workstation making intimate contact with stainless steel tweezers and an ESD sensitive device. If charge is in proximity to an ESD sensitive device, contact between metal to metal surfaces could produce an electrostatic discharge.

An F-65 current probe is positioned over the quarter and grounded stainless steel tweezers made contact with the coin (see Figures 7 and 10). In the left-hand section of Figure 8, illustrating charge on the plate, note the dip when a quarter was touched after said plate was charged to 1000 volts. This finding is due to the capacitance between the quarter and the now grounded quarter (after being touched by a person wearing a grounded wriststrap.

Product A produced a remarkable discharge curve as illustrated in Figure 8. In this case, the discharge current was 4.4 Amperes (vertical scale on the scope screen was 1 Amp/div and horizontal scale was 2 ns/div) with a subnanosecond risetime and about 2.0 ns pulse width. Six separate discharges were measured that ranged from about 3.0 Amperes to 4.4 Amperes peak. Ten years ago it would take 20mA lasting one nanosecond to kill a disk drive head.

Table 7. 12.1%RH after 48 hours.

4b). The plate voltage remained at 1023.8 volts and -1023.6 volts respectively. It should be noted that when the charge plate voltage reaches +/-1000 volts, a decay timer will start.

Product A overlaps in Table 6 and is above the limit of <2.0 seconds. Product B, however, passed as illustrated in table 6.

Faraday Cup (Q=CV) per ESD Adv. 11.2 After 48 hours of preconditioning at 12%+/-3%RH in the test chamber, Products A and B were placed under an ionizer that was balanced to less than 10 volts. Ionization removed potentially stored charges prior to Faraday cup testing. Then, the products were placed on a charge plate set at 1000 volts.

The packages were removed from the plate, grounded for a period of 5.0 seconds and allowed to free fall into a Faraday Cup as illustrated in Figure 5. Some organizations require a passing score of <+/-1.0 nC that is about <+/-100 volts.

Table 7 illustrates the results of testing for Products A and B. Product A failed the test. Product B passed the test and was within the acceptance limits.

Table 8 illustrates the Faraday Cup results. The green and purple lines exhibit the upper and lower limit of +/-1.0nC. Product A results are illustrated by a blue line and Product B is illustrated with a red line. Product B passed the test.

Non Contact Voltage Testing The technique of pinpointing hidden charges (hot spots) is accomplished by the use of a non-contact voltage mea92

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V e r m i l l i o n, S m i t h

Figure 10. Inserting tweezers through current probe. Illustrates the tweezers being inserted through the current probe.

Figure 6. The technique of pinpointing hidden charges is accomplished by the use of a non-contact voltage measurement device.

Figure 11. Notice on the left how the ionization slowly discharged the charged plate over a few seconds so that little or no discharge occurred when the quarter was touched by the tweezers.

Figure 7. An F-65 current probe is positioned over the quarter and grounded stainless steel tweezers made contact with the coin.

devices from the gelatinous type surface while Product B did not produce a discharge.

Product A with Ionization Figure 11 illustrates a small discharge current waveform of about 70 mA that occurred on four of six attempts. For two attempts, no discharge was recorded. Notice on the left side of Figure 11 how the ionization slowly discharged the charged plate over a few seconds so that little or no discharge occurred when the quarter was touched by the tweezers.

Under ionization, Product A (dark red) produced negligible to no discharges. Product B did not require ionization at 30%RH as illustrated in Figure 11 and Table 10.

Figure 8. Product A produces a remarkable discharge curve.

Conclusions In summary, the practice of anchoring components with an attraction mechanism can constitute an ESD compliant method in protecting Ultrasensitive Class 0 ESD devices but only after conducting careful evaluation and qualification of the product.

Product A gelatinous type platform for staging ESD sensitive devices measured insulative and was not in compliance with the ANSI/ESD S541-2008 (ESD Packaging & Materials) standard. Product B’s tacky-like substrate was static dissipative facilitating electrostatic decay and low charging at 12%RH. Without ionization, Product A did not prevent ESD events when conductive tweezers-quarter contact was made. However, Product A, did not pose issues under a flow of Steady State DC ionized air. In contrast, Product B did not require ionization to prevent discharges of an ESD sensitive device. Without considering the insert, both carbon loaded cases were in compliance with ANSI/ESD S541-2008. The supplier should be contacted for the product’s intended application. However, the end user must still validate supplier

Figure 9. In the case of Product B, touching the quarter by the grounded person, initiated a passing charge decay of the plate (left).

NOTE: Trigger level was set to 20 mA, which is ground zero for practical purposes.

In the case of Product B, as illustrated in Figure 9, touching the quarter by the grounded person, initiated a passing charge decay of the plate (see Figure 9 – Left). Consequently, there was no resulting discharge when the quarter was touched by stainless steel tweezers inserted through the current probe. This test was repeated six times with no discharge current recorded. Note, the vertical scale on the scope was only 100 mA/div, 10 times more sensitive than Figure 8, with a trigger level of less than 20 mA and yet still no discharge was recorded. Therefore, Product A could pose a hazard during placement and removal of ESD sensitive interferencetechnology.com

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electrostatic discharge

A C o m pa r i s o n b e t w e e n G e l at i n o u s a n d T ac k y C o at e d T y p e P ac k ag i n g C a r r i e r s

Product A Insert to Grounded Plate without Ionization

Product A Insert to Grounded Plate with Ionization

Product B Insert to Grounded Plate without Ionization

Number

mA

Start V

Number

mA

Start V

Number

mA1

Start V

1

3200

1000v

1

75

1000v

1

<20

1000v

2

3200

1000v

2

60

1000v

2

<20

1000v

3

3050

1000v

3

75

1000v

3

<20

1000v

4

3100

1000v

4

75

1000v

4

<20

1000v

5

3400

1000v

5

0

1000v

5

<20

1000v

6

4400

1000v

6

0

1000v

6

<20

1000v

Average

3392

Average

48

Average

<20

Median

3200

Median

68

Median

<20

Minimum

3050

Minimum

0

Minimum

<20

Maximum

4400

Maximum

76

Maximum

<20

St. Dev.

508

St. Dev.

37

St. Dev.

0

FAILED

PASSED

PASSED

Table 9. Contact Discharge: 30.2%RH after 24 hours of preconditioning.

1

Note: Trigger level was set to 20 mA, which is ground zero for practical purposes.

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V e r m i l l i o n, S m i t h

Bob Vermillion, CPP/Fellow, is a Certified ESD & Product Safety Engineer-iNARTE with subject matter expertise in the mitigation of Triboelectrification for a Mars surface and in troubleshooting robotics and systems for the aerospace, disk drive, medical device, pharmaceutical, automotive and semiconductor sectors. A co-author of several ANSI level ESD documents, Vermillion serves on the BoD with iNARTE and is a member of the ESDA Standards Committee. Speaking engagements include ESD Seminars in the United States and abroad and ongoing guest lecturer invitations for California State Polytechnic University, San Jose State University, University of California at Berkeley and Clemson University. In 2011, Vermillion will conduct a Materials/Packaging Seminar for Oxford University. Vermillion is Chief Technology Officer of RMV Technology Group, LLC, a NASA Industry Partner and 3rd Party ESD Materials Testing, Training and Consulting Company. He can be reached at 650-964-4792 or bob@esdrmv.com.

Table 10

claims to determine what packaging style is appropriate for use in an ESD Control Area.

Doug Smith, recently returning from lecturing at Oxford University, specializes in high-frequency measurements, circuit/system design and verification and EMC, among others. Smith's consulting activities focus on design verification and problems at the system, circuit, and device level as well as EMC and immunity (including ESD) problems. By applying specialized knowledge and measurement technology that he has developed over the years, Smith often solves design or field problems in a much smaller amount of time that could take engineers weeks, months or years of effort using conventional engineering methods of investigation. He can be reached at 408-858-4528 or doug@dsmith.org. n

Special Acknowledgement A special thank you to Mr. Brad Alhm, President,Conductive Containers, Inc. in providing samples of Product B (brada@ corstat.com).

A special thank you to Melissa Jolliff, Subject Matter Expert in the field of Electrostatic Discharge Mitigation.

References: [1]. Dr. John Kolyer and Watson, "ESD from A to Z," 2nd Edition.

[2]. Mil Handbook 1686C-1995.

[3]. Mil Handbook 263B-1994.

[4]. EIA STANDARD (defunct) Packaging Materials Standards for ESD Sensitive Items, EIA-541, June 24, 1988, Appendix C, "Triboelectric Charge Testing of Intimate Packaging Materials".

[5]. ANSI/ESD S20.20-2007 ANSI/ESD S541-2008 ANSI/ESD S3.1-2006 ANSI/ESD S4.1-2006 ANSI/ESD STM4.2-2006 ANSI/ESD STM11.11-2006 ANSI/ESD STM11.12-2007 ANSI/ESD STM11.13-2004 ESDA Adv. 11.2-1995 [6]. Albert Escusa and Bob Vermillion, "Using An ESD Packaging Materials Qualification Matrix for Contract Manufacturing and Supplier Conformance," Sep 1, 2006.

[7]. Dr. John M. Kolyer, Ph.D., Rockwell International Telephone interview in 2004.

[8]. John Kolyer and Donald Watson, The Charged Device Model & Work Surface Selection, October 1991, pp. 110-117 [9]. Humidity & Temperature Effects on Surface Resistivity, John Kolyer and Ronald Rushworth Evaluation Engineering, October 1990, pp. 106-110 Military Handbook-263B-1994 [10]. Triboelectric Testing at KSC Under Low Pressure and Temperature ESD Association Proceedings 2002, Dr. Ray Gompf, PE [11]. ITRS Technical Requirements – Electrostatics, The ITRS is devised and intended for technology assessment only and is without regard to any commercial considerations pertaining to individual products or equipment Intel Website, Moore’s Law ©2011-RMV Technology Group, LLC-All Rights Reserved. interferencetechnology.com

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