Re: Help needed about fully folded cascode OTA with PMOS inp
for analog circuit performance, i think that the length should be set 0.35um, vdd 3.3V.
hand calculation is not same to the results of simulation, it's normal, you need adjust the parameters, but in order to make the circuit work correctly, the circuit should be configure appropriately. firstly, have a ideal cmfb circuit or a ct cmfb amplifier, then, use appropriate bias or ideal bias.
the first step, simulate the dc operational point, make the outputs is cm point.
then, simulate the ac response, and adjust the parameters to meet the spec.