> EMBEDDED-FEATURE
How can Embedded Applications Ensure Small Density NOR Flash Product Longevity?
Grant Hulse
Product Marketing Manager, Memory Products Division, Microchip Technology
Typically, most small standalone and embedded systems contain an 8-bit or 16-bit microcontroller (MCU) surrounded by a collection of analog and sensor integrated circuits (ICs), display and communication interface ICs. Garage door openers, electric drills, manufacturing line equipment, medical analysis systems, etc. tend to fall under this category. Sometimes, they might even require, SRAM, EEPROM, and NOR Flash ICs if these are not present in the selected microcontroller (See Figure 1). For end equipment makers, longevity of NOR Flash ICs is a concern. Since larger density NOR Flash family members (256 Mbit to 1 Gbit+) drive the memory vendors’ business decisions, there is a constant push for smaller geometry processes and shorter product life cycles. When a move to a new process node causes an IC supplier to announce an end-of-life (EOL), it becomes necessary to requalify the device. This adds unexpected spend to existing programs since engineering resources often need to be diverted. Microchip Technology has a solution to address the NOR Flash longevity problem.
One approach to tackle this is to use a 128-Mbit NOR Flash IC to hold 4 Mbits of user programming code, thereby ‘futureproofing’ the system design. However, this can mean inefficient power consumption and higher overall system cost. Another way could be to seek out a non-traditional NOR Flash memory supplier that is equipped to supply the same memory product for 20+ years. This may result in a higher upfront cost but might work out over the course of time when one factors in the cost of requalification and involvement of engineering resources.
The Outlook for Small Density Memory
Figure 1 represents a microcontroller surrounded by other integrated circuit pieces. This gives the embedded application life and purpose. Here, the touchscreen display output IC shares a few different display images contained within the 8 Mbit NOR Flash [highlighted] as dictated by the program code (embedded in the microcontroller in this case). The key characteristics of this external NOR Flash memory IC are 1) 8 Mbits, 2) standard SPI interface, 3) low standby current, 4) low write current, 5) small area, and 6) available in production for 20 years.
As NOR Flash suppliers focus on bringing the most value and lowest cost points to their customers, they have increasingly been leaving behind their smaller density products in favour of high-margin, high-volume, high-density memory parts. The industry has been evolving towards higher density as lower density products reach EOL. These IC disruptions require that 20-year-product-life embedded system suppliers explore not just new versions of parts, but sometimes new suppliers altogether.
> MAY 2021
Microchip recognized the negative impact of this density trend on business plans and business objectives several years go. In order to remedy this, it emerged as a non-traditional NOR Flash memory IC supplier that offers serial SRAM IC, serial EEPROM IC, analog, and sensor IC products as well. Currently, it only provides for NOR Flash memory up to 64 Mbit densities, where focused memory suppliers will continue to supply product for the next 20 or more years.
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