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how to simulate this OPA
Hi, all: this is a full differential OPA which has CMFB. In this circuit, the CMFB use 4 capacitances and some switch controled by clock CKN2, CKN3, CKP2, CKP3 to supply common voltage. Now, I have a problem: how can I simulation this OPA, i.e. how can I do AC analysis for this circuit? because there have some clock singles, so I can not process AC analyse, but if I remove the clock singles, though I can do AC analyse, the CMFB may be wrong.
secondly, I find the drain of M52 and M53 connect with the gate of M51 and M50, at the same time, the source of M51 and M50 connect with the substrate of the M52 and M53, this kind of connection is so strange and I do not know why.
thirdly, what is the role of M56 and M55?
Help me, Please!!!
Hi, all: this is a full differential OPA which has CMFB. In this circuit, the CMFB use 4 capacitances and some switch controled by clock CKN2, CKN3, CKP2, CKP3 to supply common voltage. Now, I have a problem: how can I simulation this OPA, i.e. how can I do AC analysis for this circuit? because there have some clock singles, so I can not process AC analyse, but if I remove the clock singles, though I can do AC analyse, the CMFB may be wrong.
secondly, I find the drain of M52 and M53 connect with the gate of M51 and M50, at the same time, the source of M51 and M50 connect with the substrate of the M52 and M53, this kind of connection is so strange and I do not know why.
thirdly, what is the role of M56 and M55?
Help me, Please!!!