AD4195-4 Offset Drift Data with Chop Enabled

Hi NAKAJI ,

As mentioned previously, since we don't have any guaranteed specification for the offset drift with chop enabled, there has only been a functionality test with the device. With this functionality test, it shows that the offset improved which is expected when chopping is enabled.

Functionally, enabling ADC/multiplexer chopping periodically swaps the positive and negative inputs, takes conversions for each polarity, and averages the two results. This cancels most static offset terms that change sign with input reversal and thereby minimizes both offset and offset drift. It also improves RMS noise by about √2 (≈0.5 bits p‑p), at the expense of increased settling time and reduced effective output data rate (particularly with the Sinc³ filter).

For system‑level guidance, if your application prioritizes DC stability over throughput, we recommend operating with CHOP_ADC enabled and using the datasheet’s standard offset and drift limits as a worst‑case bound, with the understanding that chopping will reduce typical offset and drift below those limits but without a separate guaranteed number.

Thanks,
Francis

Hi Francis,

Thank you for your detailed explanation.

This is very helpful for explaining the expected behavior to our customer.

Thank you again for your support.

Best regards,
NAKAJI

Hi Francis,

Thank you for your detailed explanation.

This is very helpful for explaining the expected behavior to our customer.

Thank you again for your support.

Best regards,
NAKAJI