stm32L431KB suffix 3 vs suffix 6 differences other than temp rating?

[PLivi.1]

Hello, so I have been struggling lately to find a bug in the software that ran perfectly on stm32L431KBU6. And after much trial and error with dumb luck, I found out that the software still works flawlessly on suffix 6 but recently I had been building the project with suffix 3 and I get resets on some weird situations. Now comes the big question, what are the working differences between suffix 6 and suffix 3 besides max temperature handling of the part itself? Are there differences like temp sensor, ADC, etc? Anything that can enlighten me would be much appreciated. This is getting frustrating 🙂

Gabriel

[Uwe Bonnes]

The datasheet only give a difference in temperature range. So as long as you work inside the limits given in the datasheet, I expect no differenc in behaviour. I suspect however that some of your settings like flash wait state, bus frequency,supply voltage etc. is outside of the allowed range and the -6 part does still work while the -3 part does not.

[PLivi.1]

This would imply that the 3 part is different. and no, there are no limits crossed.

[PLivi.1]

So because nobody answered I could say I found the issue I was having. The 3 suffix seems a little more unstable on the NRST. So the 6 suffix is just fine without any cap on NRTS but the 3 suffix has parasitic Reset triggers (the actual line stays at 3.3v no issues but just slight noise is present. Don't know if it is just the 3 suffix or a different batch of ic's but this is what I noticed. Thanks.

[Uwe Bonnes]

Do tou have the recommended ~100nF to ground on NRST?

[Piranha]

> find a bug in the software

> just fine without any cap on NRTS

As always... No, no part is fine without a capacitor on NRST.

[PLivi.1]

Yeah, I know but this was not designed by me, just noticed the problem I guess this is just a learned lesson 🙂