now, i want to design a very low power opamp (miller two-stage or symmetric single stage), what is the minimum value of branch current that can be accepted in normal 0.35um process?
if the bias current is 100nA (or lower) for every branch, what problems can be generated? and what considerations should be take for the low power opamp design? if the bias current is very small (nA order), then, what is the influence on offset, leakage, mismatch, and so on? can subthreshold leakage happen? besides, how is leakage current generated? is it related to body effect or subthreshold operation?

thanks all.

start with some basic research.