Hi,
In the article below it describes the way to achieve zero offset for an amp.
I would like to know what's the chopping frequency? I don't need a very specific number, maybe tens of kHz or hundreds of kHz?
And will there be chopping frequency distortion at the output?
As Kai mentioned, OPA388 chopping frequency is around 200kHz - see below.
As far as the output distortion goes, it is unlikely to be seen unless a high gain or/and large unmatched input resistors are used - see below ways to mitigate the potential issue.
Any remaining distortion at the output may be eliminated with addition of the low pass filter.
