Latch-Up Test

[epccs]

The last page of this app note describes how to evaluate CMOS for Latch-Up.

https://www.onsemi.com/pub/Collateral/AN-339.pdf.pdf

AVR 32[48]pb might be susceptible to destructive latch-up; it is not clear from anything I have seen.

https://en.wikipedia.org/wiki/Latch-up

My thinking has been that the "trench" industry-standard technique helps to limit the destructive current, but some discussion and things like that On/Fairchild Semiconductor application note changed my mind.

Microchip corporation is going to be releasing a new line of AVR128DA that will target safety-critical industrial applications. Those will hopefully address some of these problems that can occur when microcontrollers are trusted to operate the equipment reliably.

https://www.microchip.com/wwwproducts/en/AVR128DA64

With that said, it should be evident that a more industrial worthy path forward will be to replace the 328pb and 324pb (perhaps with AVR128DA32 and AVR128DA48). However, development with the current parts will continue for the near term.

When a datasheet says must not be used within "safety critical" System that may be a clue about latch-up being a known issue.