lhlbluesky_lhl
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i have designed a two stage opamp (used for a buffer, fck=15M, CL=12pF), the first stage is folded cascode, the second is common source, and i use cascode compensation to ensure frequency stability, now, i get the following simulation curve, when the input signal from 0.4 to 1.6, it settles well, but when the input signal from 1.6 to 0.4, it has a very big overshoot, why? the PM is 70 deg or so, and it is not like normal underdamped oscilation, what is the reason of this big overshoot? please give me some advice, thanks all.
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