While ambient testing our product, we have noticed a considerable drift as the temperature increases (upto 70C).
This drift is in the order of nearly 100uV and is present across AIN0/1, both with a thermopile (86kohm nominal) or a resistor (70kohm) connected. This offset is not present if the inputs are shorted and in typical operation one of the inputs is biased using the onboard bandgap reference.
The ADC is configured with buffers enabled, a gain of 64 and utilising the notch filter and chop.
This drift is nonlinear but predictable however, it varies across devices therefore making compensation difficult.
We have used your standalone ADCs before with similar specifications without seeing this issue.
Please advise urgently!