STSPIN32G4-ADC-error

[qxy]

When using the STSPIN32G4 chip, the ADC uses an external resistor for non-inverting amplification to determine the value, but in reality, the ADC-OUT output is always at the maximum of its internal LDO. Changing the external feedback resistor can't change the output value of its op-amp. What could be the reason for this? Also, the voltage difference on the non-inverting side of the three op-amps is inconsistent: two are 0.27, and one is 0.35. I’d like to ask the experts for advice.

[GMA]

Hello ​@qxy,

 

What board are you referring to?

[db16122]

Maybe you need to check with the VREF

VREF+ is the input reference voltage for ADCs and DACs. It is also the output of the internal voltage reference buffer when enabled.