In Fig. 26.16 can't we remove the φ2 switches on the bottom of C2 for

better operation? Won't keeping those switches create an error in the

output common-mode voltage?


The problem with removing those φ2-controlled switches is that then there

isn't a DC path to VCMFB. VCMFB is only connected to capacitors or the gates

of MOSFETs (so its initial value is unknown and uncontrollable).


Yes, there will be an offset in the output common-mode voltage. This offset,

as discussed on page 875 is set by difference between the ideal VCMFB and the

actual VCMFB. In Fig. 26.16 the ideal VCMFB is Vbiasn.