Hi,

I'm simulating a flip around track and hold circuit as 1st  block for a 10bit pipeline ADC.  circuit diagram and output waveform are as below: when I measure the THD at A (differential) it's ~-80dB, however only ~-30dB at B.  all switches are bootstrapped ones and op-amp works fine (enough gain, no stb issue).

my questions are :
1. ideally, should A and B give the same THD ( A tracks and hold the input sinusoidal wave, B is either 0 or the hold value of A); how much degradation should we expect in practice.
2. how do i improve THD at B, which is actually the input of the 1st pipeline stage (other than impoving feedback switch)

Thanks a lot,
SteveEdited:
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