Max input ADC below Vss F411

[stm32forum]

Posted on March 26, 2015 at 15:01

I was wondering what the negative input can be on an ADC pin.

We have an analog signal that can be very rare -38mV for a short moment. In the datasheet page 60 of the F411 i can only find Absolute maximum ratings: Input voltage on FT and TC pins  VSS –0.3 So it looks I'm within the marge, is that correct ?

[AvaTar]

Posted on March 26, 2015 at 15:59

...i can only find Absolute maximum ratings: Input voltage on FT and TC pins  VSS –0.3

There is, at least in my F40x datasheet, and additional column ''Unit'', which says ''V''. That means -300mV, so -38mV is in limits. However, protective measures are probably advisable. For small and low power negative surges, a schottky diode might be sufficient.