So I came across this circuit in my analog electronics course. I am not sure on how to account for the capacitors and I couldn't find a similar circuit anywhere else. So how do I solve this circuit for gain?
1 Answer
The most direct way is to use nodal or loop relations. 1) (Vin-Vx)*C1*s=(Vx-Vo)*C2*s 2) (Vx-Vo)*C2*s=Vxgm+Vogo Eliminate Vx. Answer above is low frequency so let s->0 in solution.
Full solution is Vo/Vin=C1s{1/(C1s+C2s)}(C2s-gm){1/(go+C2s)}/{1-C2s*{1/(C1s+C2s)}(C2s-gm){1/(go+C2s)} where go=1/ro with gm models the mos transistor
Cancel out 's' terms in cap division factors, drop out C2s in (C2s-gm) factor and finally let s=0 in final to get solution you are looking for.
The full solution is best found using dpi/sfg as shown in Feedback in Analog Circuits by A. Ochoa