Datasheet OP777AR by Antonio Packer

a FEATURES Low Offset Voltage: 100 V Max Low Input Bias Current: 10 nA Max Single-Supply Operation: 2.7 V to 30 V Dual-Supply Operation: 1.35 V to 15 V Low Supply Current: 270 A/Amp Unity Gain Stable No Phase Reversal APPLICATIONS Precision Current Measurement Line or Battery-Powered Instrumentation Remote Sensors Precision Filters

Precision Micropower Single Supply Operational Amplifier OP777 FUNCTIONAL BLOCK DIAGRAMS 8-Lead MSOP (RM Suffix) NC IN IN V

NC V+ OUT NC

OP777 4

NC = NO CONNECT

8-Lead SOIC (R Suffix) NC 1 IN 2 +IN 3 V 4

8 NC

OP777

7 V+ 6 OUT 5 NC

NC = NO CONNECT

GENERAL DESCRIPTION

The OP777 is a precision single supply amplifier featuring micropower operation and rail-to-rail output ranges. This amplifier provides improved performance over the industry-standard OP07 with ± 15 V supplies and offers the further advantage of true single supply operation down to 2.7 V, and smaller package footprint than any other high-voltage precision bipolar amplifier. Outputs are stable with capacitive loads of over 1000 pF. Supply current is less than 300 µA per amplifier at 5 V. 500 Ω series resistors protect the inputs, allowing input signal levels to exceed either power supply rail by up to 3 V without causing phase reversal of the output signal or causing damage to the amplifier. The proprietary fabrication process yields a very low-voltage noise corner frequency under 10 Hz, greatly improving the low-frequency noise performance of the OP07 and similar amplifiers. The specially fabricated input PNP transistors operate with very low input bias currents while allowing operation with large differential voltages, eliminating a common limitation of many precision amplifiers and enabling application of the OP777 in precision comparator and rectifier circuits. This large differential voltage capability also further reduces the need for external protection devices such as clamping diodes.

Applications for these amplifiers include both line powered and portable instrumentation, remote sensor signal conditioning, and precision filters. The OP777 is specified over the extended industrial (–40°C to +85°C) temperature range and is available in 8-lead MSOP and 8-lead SOIC packages. The OP777 uses a standard operational amplifier pinout, allowing for easy drop-in replacement of lower performance amplifiers in most circuits. Surface mount devices in MSOP packages are available in tape and reel only.

REV. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 © Analog Devices, Inc., 2000

OP777–SPECIFICATIONS ELECTRICAL CHARACTERISTICS (V = 5.0 V, V S

Parameter

Symbol

INPUT CHARACTERISTICS Offset Voltage

VOS

= 2.5 V, TA = 25 C unless otherwise noted)

Conditions

Min

IB IOS

–40°C ≤ TA ≤ +85°C –40°C ≤ TA ≤ +85°C –40°C ≤ TA ≤ +85°C

CMRR AVO ∆VOS /∆T

VCM = 0 V to 4 V RL = 10 kΩ , VO = 0.5 V to 4.5 V –40°C ≤ TA ≤ +85°C

OUTPUT CHARACTERISTICS Output Voltage High Output Voltage Low Short Circuit Limit

VOH VOL IOUT

IL = 1 mA, –40°C ≤ TA ≤ +85°C IL = 1 mA, –40°C ≤ TA ≤ +85°C VDROPOUT < 1 V

4.88

POWER SUPPLY Power Supply Rejection Ratio Supply Current/Amplifier

PSRR ISY

VS = 3 V to 30 V VO = 0 V –40°C ≤ TA ≤ +85°C

120

Input Bias Current Input Offset Current Input Voltage Range Common-Mode Rejection Ratio Large Signal Voltage Gain Offset Voltage Drift

0 104 300

Typ

110 500 0.3

Max

Unit

100 200 11 2 4

µV µV nA nA V dB V/mV µV/°C

1.3

140

V mV mA

270 320

dB µA µA

± 10 130 270

DYNAMIC PERFORMANCE Slew Rate Gain Bandwidth Product

SR GBP

RL = 2 kΩ

0.2 0.7

V/µs MHz

NOISE PERFORMANCE Voltage Noise Voltage Noise Density Current Noise Density

enp-p en in

0.1 Hz to 10 Hz f = 1 kHz f = 1 kHz

0.4 15 0.13

µVp-p nV/√Hz pA/√Hz

Specifications subject to change without notice.

–2–

REV. 0

OP777 ELECTRICAL CHARACTERISTICS (V = 15.0 V, V S

Parameter

Symbol

INPUT CHARACTERISTICS Offset Voltage

VOS

= 0 V, TA = 25 C unless otherwise noted)

Conditions

Min

IB IOS

–40°C ≤ TA ≤ +85°C –40°C ≤ TA ≤ +85°C –40°C ≤ TA ≤ +85°C

CMRR AVO ∆VOS /∆T

VCM = –15 V to +14 V RL = 10 kΩ , VO = –14.5 V to +14.5 V –40°C ≤ TA ≤ +85°C

OUTPUT CHARACTERISTICS Output Voltage High Output Voltage Low Short Circuit Limit

VOH VOL IOUT

IL = 1 mA, –40°C ≤ TA ≤ +85°C IL = 1 mA, –40°C ≤ TA ≤ +85°C

14.9

POWER SUPPLY Power Supply Rejection Ratio Supply Current/Amplifier

PSRR ISY

VS = ± 1.5 V to ± 15 V VO = 0 V –40°C ≤ TA ≤ +85°C

120

Input Bias Current Input Offset Current Input Voltage Range Common-Mode Rejection Ratio Large Signal Voltage Gain Offset Voltage Drift

–15 110 1,000

Typ

Max

Unit

100 200 10 2 +14

µV µV nA nA V dB V/mV µV/°C

120 2,500 0.3 1.3

–14.9 ± 30 130 350

350 400

V V mA dB µA µA

DYNAMIC PERFORMANCE Slew Rate Gain Bandwidth Product

SR GBP

RL = 2 kΩ

0.2 0.7

V/µs MHz

NOISE PERFORMANCE Voltage Noise Voltage Noise Density Current Noise Density

enp-p en in

0.1 Hz to 10 Hz f = 1 kHz f = 1 kHz

0.4 15 0.13

µVp-p nV/√Hz pA/√Hz

Specifications subject to change without notice.

REV. 0

–3–

OP777 ABSOLUTE MAXIMUM RATINGS*

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 V Input Voltage . . . . . . . . . . . . . . . . . . . . . VS– – 3 V to VS+ + 3 V Differential Input Voltage . . . . . . . . . . . . . . ± Supply Voltage Output Short-Circuit Duration to GND . . . . . . . . . Indefinite Storage Temperature Range R, RM Packages . . . . . . . . . . . . . . . . . . . . –65°C to +150°C Operating Temperature Range OP777 . . . . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C Junction Temperature Range R, RM Packages . . . . . . . . . . . . . . . . . . . . –65°C to +150°C Lead Temperature Range (Soldering, 60 sec) . . . . . . . . 300°C ESD (HBM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 kV

Package Type

JA1

Unit

8-Lead MSOP (RM) 8-Lead SOIC (R)

190 158

44 43

°C/W °C/W

NOTE 1 θJA is specified for worst-case conditions, i.e., θJA is specified for device soldered in circuit board for surface-mount packages.

*Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

ORDERING GUIDE

Model

Temperature Range

Package Description

Package Option

Branding Information

OP777ARM OP777AR

–40°C to +85°C –40°C to +85°C

8-Lead MSOP 8-Lead SOIC

RM-8 SO-8

A1A

CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the OP777 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

–4–

WARNING! ESD SENSITIVE DEVICE

REV. 0

Typical Performance Characteristics–OP777

160 140 120 100 80 60

140 120 100 80 60

0 100 80 60 40 20 0 20 40 60 80 100 OFFSET VOLTAGE – V

Figure 2. Input Offset Voltage Distribution

SINK

100

SOURCE 10

1.0

5 7 4 6 INPUT BIAS CURRENT – nA

0 0.001

Figure 4. Input Bias Current Distribution

0.01

0.1 1 10 LOAD CURRENT – mA

400

0 5 10 15 20

SUPPLY CURRENT – A

200 100

ISY+ (VSY = 5V)

0 100 200 ISY (VSY = 5V)

300 400

30 60 40 20 0 20 40 60 80 100 120 140 TEMPERATURE – C

500 60 40 20 0 20 40 60 80 100 120 140 TEMPERATURE – C

REV. 0

SINK

1.0

SOURCE

0.01

0.1 1 10 LOAD CURRENT – mA

100

350 TA = 25 C

ISY+ (VSY = 15V)

Figure 7. Input Bias Current vs. Temperature

100

Figure 6. Output Voltage to Supply Rail vs. Load Current

500 VSY = 15V

VS = 15V TA = 25 C

0 0.001

100

Figure 5. Output Voltage to Supply Rail vs. Load Current

1.2

0.1

0.2 0.4 0.6 0.8 1.0 INPUT OFFSET DRIFT – V/ C

Figure 3. Input Offset Voltage Drift Distribution

OUTPUT VOLTAGE – mV

VS = 5V TA = 25 C

OUTPUT VOLTAGE – mV

10k

10k VSY = 15V VCM = 0V TA = 25 C

NUMBER OF AMPLIFIERS

160

Figure 1. Input Offset Voltage Distribution

INPUT BIAS CURRENT – nA

180

VSY = 15V VCM = 0V TA = 40 C TO +85 C

ISY (VSY = 15V)

Figure 8. Supply Current vs. Temperature

–5–

300 SUPPLY CURRENT – A

NUMBER OF AMPLIFIERS

180

VSY = 5V VCM = 2.5V TA = 25 C

200 NUMBER OF AMPLIFIERS

200

220

VSY = 15V VCM = 0V TA = 25 C

NUMBER OF AMPLIFIERS

220

250 200 150 100 50 0

10 15 20 25 SUPPLY VOLTAGE – V

Figure 9. Supply Current vs. Supply Voltage

OP777 0

135

180

225

270

135

180

225

270

30 100

100

1k 10k 100k 1M FREQUENCY – Hz

10M 100M

AV = 100

30 AV = 10

0 10

AV = +1

20 30 40 1k

10M

10k

100k 1M 10M FREQUENCY – Hz

Figure 13. Closed Loop Gain vs. Frequency

150 120 90 AV = 100

AV = 10

100k 10k 1M FREQUENCY – Hz

10M

AV = +1

10k

100M

100k 1M 10M FREQUENCY – Hz

VSY = 15V

240 210

AV = 1

180 150 120 90 60

AV = 100 AV = 10

0 100

100M

TIME – 100 s/DIV

Figure 17. Large Signal Transient Response

–6–

10k 1M 100k FREQUENCY – Hz

10M

100M

Figure 15. Output Impedance vs. Frequency

VSY = 15V RL = 2k CL = 300pF VOLTAGE – 1V/DIV

Figure 16. Large Signal Transient Response

Figure 14. Output Impedance vs. Frequency

VSY = 2.5V RL = 2k CL = 300pF

TIME – 100 s/DIV

270

180

0 100

AV = 10

300

AV = 1

210

100M

Figure 12. Closed Loop Gain vs. Frequency

VSY = 5V

240

40 1k

100M

VOLTAGE – 1V/DIV

CLOSED-LOOP GAIN – dB

10k 1M 100k FREQUENCY – Hz

270 OUTPUT IMPEDANCE –

VSY = 5V CLOAD = 0 RLOAD = 2k

300

AV = 100

Figure 11. Open Loop Gain and Phase Shift vs. Frequency

Figure 10. Open Loop Gain and Phase Shift vs. Frequency

VOLTAGE – 50mV/DIV

VSY = 15V CLOAD = 0 RLOAD = 2k

50 PHASE SHIFT – Degrees

OUTPUT IMPEDANCE –

OPEN-LOOP GAIN – dB

VSY = 5V CLOAD = 0 RLOAD =

CLOSED-LOOP GAIN – dB

OPEN-LOOP GAIN – dB

VSY = 15V CLOAD = 0 RLOAD =

PHASE SHIFT – Degrees

VSY = 2.5V CL = 300pF RL = 2k VIN = 100mV

TIME – 10 s/DIV

Figure 18. Small Signal Transient Response

REV. 0

OP777 40

30 25 20 15 10 5 0

100 10 CAPACITANCE – pF

TIME – 10 s/DIV

Figure 19. Small Signal Transient Response

VSY = 2.5V RL = 2k VIN = 100mV

SMALL SIGNAL OVERSHOOT – %

VOLTAGE – 50mV/DIV

VSY = 15V CL = 300pF RL = 2k VIN = 100mV

25 +OS 20 OS 15 10 5 0

Figure 20. Small Signal Overshoot vs. Load Capacitance

VSY = 15V RL = 2k VIN = 100mV

1k 10 100 CAPACITANCE – pF

10k

Figure 21. Small Signal Overshoot vs. Load Capacitance

VS = 15V AV = 1

INPUT

INPUT +200mV

VSY = 15V RL = 10k AV = 100 VIN = 200mV

VSY = 2.5V RL = 10k AV = 100 VIN = 200mV

200mV

+2V

0V 2V

VOLTAGE – 5V/DIV

INPUT 0V

OUTPUT

0V OUTPUT

OUTPUT

TIME – 40 s/DIV

TIME – 400 s/DIV

TIME – 40 s/DIV

Figure 22. Positive Overvoltage Recovery

Figure 23. Negative Overvoltage Recovery

140

VSY = 2.5V

Figure 24. No Phase Reversal

140

VSY = 15V

VSY = 2.5V

120

100

80 60

PSRR – dB

CMRR – dB

+PSRR

80 60

PSRR 80 60

100

10k 100k 1k FREQUENCY – Hz

Figure 25. CMRR vs. Frequency

REV. 0

10M

100

10k 100k 1k FREQUENCY – Hz

10M

Figure 26. CMRR vs. Frequency

–7–

100

10k 100k 1k FREQUENCY – Hz

Figure 27. PSRR vs. Frequency

10M

OP777 140

VSY = 15V

+PSRR 80 PSRR 60 40

VOLTAGE – 1V/DIV

100 PSRR – dB

VSY = 15V GAIN = 10M

VSY = 5V GAIN = 10M

120

100

10k 100k 1k FREQUENCY – Hz

10M

Figure 28. PSRR vs. Frequency

Figure 29. 0.1 Hz to 10 Hz Input Voltage Noise

80 70 60 50 40 30 20

VSY = 2.5V

VOLTAGE NOISE DENSITY – nV/ Hz

VSY = 15V

VOLTAGE NOISE DENSITY – nV/ Hz

Figure 30. 0.1 Hz to 10 Hz Input Voltage Noise

80 70 60 50 40 30 20 10

10 0

100 150 FREQUENCY – Hz

200

250

Figure 31. Voltage Noise Density

100

200 300 FREQUENCY – Hz

400

SHORT CIRCUIT CURRENT – mA

30 25 20 15 10 5 0 0

500

1k 1.5k FREQUENCY – Hz

2.0k

2.5k

Figure 34. Voltage Noise Density

60 50 40 30 20

100

200 300 FREQUENCY – Hz

30 20

ISC

10 0 10 20

ISC+

400

500

Figure 33. Voltage Noise Density

VSY = 5V

50 VSY = 2.5V

VSY = 15V 80

500

Figure 32. Voltage Noise Density

VOLTAGE NOISE DENSITY – nV/ Hz

TIME – 1s/DIV

VSY = 15V

40 SHORT CIRCUIT CURRENT – mA

30 20

ISC

10 0 10 20 30

ISC+

50 60 40 20 0 20 40 60 80 100 120 140 TEMPERATURE – C

Figure 35. Short Circuit Current vs. Temperature

Figure 36. Short Circuit Current vs. Temperature

–8–

REV. 0

OP777 160

4.94

150

OUTPUT VOLTAGE LOW – mV

OUTPUT VOLTAGE HIGH – V

VSY = 5V IL = 1mA

4.93

4.92

4.91

4.90

14.964

VSY = 5V IL = 1mA

14.962 OUTPUT VOLTAGE HIGH – V

4.95

140 130 120 110 100 90 80

Figure 37. Output Voltage High vs. Temperature

14.935

Figure 38. Output Voltage Low vs. Temperature

1.5

VSY = 15V IL = 1mA

14.940 14.945

0.5 0

14.950

0.5

14.955

1.0

14.960 60 40 20 0 20 40 60 80 100 120 140 TEMPERATURE – C

1.5

Figure 40. Output Voltage Low vs. Temperature

REV. 0

VSY = 15V VCM = 0V TA = 25 C

1.0

VOS – V

OUTPUT VOLTAGE LOW – V

14.930

14.960 14.958 14.956 14.954 14.952 14.950 14.948 14.946

70 60 40 20 0 20 40 60 80 100 120 140 TEMPERATURE – C

4.89 60 40 20 0 20 40 60 80 100 120 140 TEMPERATURE – C

VSY = 15V IL = 1mA

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 TIME – Minutes

Figure 41. Warm-Up Drift

–9–

14.944 60 40 20 0 20 40 60 80 100 120 140 TEMPERATURE – C

Figure 39. Output Voltage High vs. Temperature

OP777 BASIC OPERATION

100k

The OP777 amplifier uses a precision Bipolar PNP input stage coupled with a high-voltage CMOS output stage. This enables this amplifier to feature an input voltage range which includes the negative supply voltage (often ground-in single-supply applications) and also swing to within 1 mV of the output rails. Additionally, the input voltage range extends to within 1 V of the positive supply rail. The epitaxial PNP input structure provides high breakdown voltage, high gain, and input bias current figure comparable to that obtained with “Darlington” input stage amplifier but without the drawbacks (i.e., severe penalties for input voltage range, offset, drift and noise). PNP input structure also greatly lowers the noise and reduces the dc input error terms.

100k

+3V

0.27V 100k

OP777 100k 0.1V VIN = 1kHz at 400mV p-p

Figure 43. OP777 Configured as a Difference Amplifier Operating at VCM < 0 V Input Over Voltage Protection

Supply Voltage

The amplifiers are fully specified with a single 5 V supply and, due to design and process innovations, can also operate with a supply voltage from 2.7 V up to 30 V. This allows operation from most split supplies used in current industry practice, with the advantage of substantially increased input and output voltage ranges over conventional split-supply amplifiers. The OP777 series is specified with (VSY = 5 V, V– = 0 V and VCM = 2.5 V which is most suitable for single supply application. With PSRR of 130 dB (0.3 µV/V) and CMRR of 110 dB (3 µV/V) offset is minimally affected by power supply or common-mode voltages. Dual supply, ±15 V operation is also fully specified. Input Common-Mode Voltage Range

The OP777 is rated with an input common-mode voltage which extends from minus supply to 1 V of the Positive supply. However, the amplifier can still operate with input voltages slightly below VEE. In Figure 43, OP777 is configured as a difference amplifier with a single supply of 2.7 V and negative dc common-mode voltages applied at the inputs terminals. A 400 mV p-p input is then applied to the noninverting input. It can be seen from the graph below that the output does not show any distortion. Micropower operation is maintained by using large input and feedback resistors.

When the input of an amplifier is more than a diode drop below VEE, large currents will flow from the substrate (V– pin) to the input pins which can destroy the device. In the case of OP777, differential voltage equal to the supply voltage will not cause any problem (see Figure 44). OP777 has built in 500 Ω internal current limiting resistors, in series with the inputs, to minimize the chances of damage. It is a good practice to keep the current flowing into the inputs below 5 mA. In this context it should also be noted that the high breakdown of the input transistors removes the necessity for clamp diodes between the inputs of the amplifier; a feature that is mandatory on many precision op amps. Unfortunately, such clamp diodes greatly interfere with many application circuits such as precision rectifiers and comparators. The OP777 series is free from such limitations.

30V

OP777

V p-p = 32 V

VOUT

VIN

VSY = 15V

VOLTAGE – 5V/DIV

VOLTAGE – 100 V/DIV

Figure 44a. Unity Gain Follower

VIN

VOUT

TIME – 0.2ms/DIV

Figure 42. Input and Output Signals with VCM < 0 V TIME – 400 s/DIV

Figure 44b. Input Voltage Can Exceed the Supply Voltage Without Damage

–10–

REV. 0

OP777 Phase Reversal

Output Short Circuit

Many amplifiers misbehave when one or both of the inputs are forced beyond the input common-mode voltage range. Phase reversal is typified by the transfer function of the amplifier, effectively reversing its transfer polarity. In some cases this can cause lockup in servo systems and may cause permanent damage or nonrecoverable parameter shifts to the amplifier. Many amplifiers feature compensation circuitry to combat these effects, but some are only effective for the inverting input. Additionally, many of these schemes only work for a few hundred millivolts or so beyond the supply rails. OP777 has a protection circuit against phase reversal when one or both inputs are forced beyond their input common voltage range. It is not recommended that the parts be continuously driven more than 3 V beyond the rails.

The output of the OP777 series amplifier is protected from damage against accidental shorts to either supply voltage, provided that the maximum die temperature is not exceeded on a long-term basis (see Absolute Maximum Rating section). Current of up to 30 mA does not cause any damage.

VSY = 15V

VOLTAGE – 5V/DIV

VIN

VOUT

A Low-Side Current Monitor

In the design of power supply control circuits, a great deal of design effort is focused on ensuring a pass transistor’s long-term reliability over a wide range of load current conditions. As a result, monitoring and limiting device power dissipation is of prime importance in these designs. Figure 48 shows an example of 5 V, single supply current monitor that can be incorporated into the design of a voltage regulator with foldback current limiting or a high current power supply with crowbar protection. The design capitalizes on the OP777’s common-mode range that extends to ground. Current is monitored in the power supply return where a 0.1 Ω shunt resistor, RSENSE, creates a very small voltage drop. The voltage at the inverting terminal becomes equal to the voltage at the noninverting terminal through the feedback of Q1, which is a 2N2222 or equivalent NPN transistor. This makes the voltage drop across R1 equal to the voltage drop across RSENSE. Therefore, the current through Q1 becomes directly proportional to the current through RSENSE, and the output voltage is given by:  R2  VOUT = 5 V −  × RSENSE × I L   R1 

TIME – 400 s/DIV

Figure 45. No Phase Reversal Output Stage

The CMOS output stage has excellent (and fairly symmetric) output drive and with light loads can actually swing to within 1 mV of both supply rails. This is considerably better than similar amplifiers featuring (so-called) rail-to-rail bipolar output stages. OP777 is stable in the voltage follower configuration and responds to signals as low as 1 mv above ground in single supply operation.

The voltage drop across R2 increases with IL increasing, so VOUT, decreases with higher supply current being sensed. For the element values shown, the VOUT transfer characteristic is –2.5 V/A, decreasing from VEE. 5V 2.49k VOUT Q1 5V

2.7V TO 30V

OP777

100

VOUT = 1mV VIN = 1mV

0.1

OP777

RSENSE

Figure 48. A Low-Side Load Current Monitor

VOLTAGE – 25mV/DIV

Figure 46. Follower Circuit

1.0mV

TIME – 10 s/DIV

Figure 47. Rail-to-Rail Operation

REV. 0

RETURN TO GROUND

–11–

OP777 The OP777 can be very useful in many single supply bridge applications. Figure 49 shows a single supply bridge circuit in which its output is linearly proportional to the fractional deviation ( ) of the bridge. Note that = ∆R/R.

REF 192 4

2.7V TO 30V 100k 100k

10.1k

2.5V REF 192

10pF

OP777

R1 = 100k

0.1 F

R2B 2.7k

15V 15V

R1(1+ ) V1

10pF

10.1k R2 = R2A + R2B

OP777 R1(1+ )

IO =

OP777

C3865–2.5–4/00 (rev. 0) 01536

OP777

VL ≤ VSAT − VS

= 300 AR1 VREF VO = + 2.5V 2R2 R1 = R1 RG = 10k

15V

A single supply current source is shown in Figure 51. Large resistors are used to maintain micropower operation. Output current can be adjusted by changing the R2B resistor. Compliance voltage is:

R2A 97.3k

R2 V R1 R2B S

= 1mA 11mA V2

RLOAD

Figure 51. Single Supply Current Source

Figure 49. Linear Response Bridge, Single Supply

In systems, where dual supplies are available, circuit of Figure 50 could be used to detect bridge outputs that are linearly related to fractional deviation of the bridge.

A single supply instrumentation amplifier using two OP777 amplifiers is shown in Figure 52.

15V

10.1k

R2 = 1M

2.7V TO 30V 1k REF 192

R1 = 10.1k

OP777

12k

OP777

3 20k

V2 VO = 100 (V2 V1) 0.02mV V1 V2 2mV VOUT 29V

R(1+ )

+15V

OP777 15V

USE MATCHED RESISTORS R2 V R1 REF R = R

VO =

OP777 15V

290mV

Figure 52. Single Supply Micropower Instrumentation Amplifier

Figure 50. Linear Response Bridge

OUTLINE DIMENSIONS Dimensions shown in inches and (mm).

8-Lead SOIC (RM Suffix)

8-Lead SOIC (R Suffix)

0.122 (3.10) 0.114 (2.90)

0.1968 (5.00) 0.1890 (4.80) 8

0.1574 (4.00) 0.1497 (3.80) 1

0.199 (5.05) 0.187 (4.75)

0.122 (3.10) 0.114 (2.90) 1

5 4

0.2440 (6.20) 0.2284 (5.80)

PIN 1 0.0098 (0.25) 0.0040 (0.10)

PIN 1 0.0256 (0.65) BSC 0.120 (3.05) 0.112 (2.84) 0.006 (0.15) 0.002 (0.05) 0.018 (0.46) SEATING 0.008 (0.20) PLANE

0.120 (3.05) 0.112 (2.84) 0.043 (1.09) 0.037 (0.94) 0.011 (0.28) 0.003 (0.08)

33 27

0.0688 (1.75) 0.0532 (1.35)

0.0500 0.0192 (0.49) SEATING (1.27) 0.0098 (0.25) PLANE BSC 0.0138 (0.35) 0.0075 (0.19)

0.0196 (0.50) x 45° 0.0099 (0.25)

8° 0° 0.0500 (1.27) 0.0160 (0.41)

0.028 (0.71) 0.016 (0.41)

–12–

REV. 0

PRINTED IN U.S.A.

2.7V TO 30V

1M 2N2222