opamp with the capacitive feedback

[savikx]

hi, assume a opamp with the capactive feedback
if the input cap is C1, and the feedback cap C2.
We know that the gain is -C1/C2, if the open-loop gain is sufficient large.
what the problem I may encounter if the feedback cap is very small (ex:50fF or 20fF), with input cap=20pF. Under the same capacitance load condition and open-loop gain=80dB.

thanks

 

[A.Anand Srinivasan]

the noise and leakage associated with the capacitors would have very high influence on the output...