Thanks a lot for the clarification Peter. To be honest, I cannot follow the code and how the look-up table was built. It looks very specific to the design. Means if other component values or settings are used it might not work anymore. However as you seem to get reasonable results, I would assume it is working in your case. (And yes, I fully agree, the comments are a mess.) The 25ppm/°C RREF would align with my error calculations. But then using a 2ppm/°C RREF should definitely improve the drift performance. We usually recommend RREFs with a drift in the <=5ppm/°C range. I am not sure where else the drift should come from. The ADC itself only has a gain drift in the 2ppm/°C range and you are removing the offset drift in principle by doing the "chopped" measurements. Regards, Joachim Wuerker
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