Hi,

While it is true that the pole-zero locations will change with the signal level and hence in a switched-cap circuit over the clock phase, I think that the common stability criteria still need to be applied. However, you are generally forced to use transient analysis (step response) under all possible conditions (proces, voltage, temperature, large & small signals) to verify that settling behavior is OK.

When you do a small-signal stability analysis, then you are going to see results for the stability of the opamp towards the end of the clock phase (when all large transients have died out). If you have insufficient phase margin, then it would mean that any disturbance anywhere, it will potentially start another round of ringing and so your settling performance will be ruined. So, stability margins are not something you can compromise on. That bein g said, it is generally possible to use single-stage class-AB amps in switched-capacitor applications (depends on the gain you are trying to achieve) which are inherently more stable than multi-stage class-AB.

Regards,
Vivek