I am studying a chopper amplifier circuit and have come across the idea of effective dc gain of opamp. The effective dc gain of the opamp due to chopping is the gain at the chopping frequency. Please look at the following schematic. The top is a capacitive feedback amplifier circuit incorporating a chopper op and the bottom is the chopper op used. The op is an ideal model and has one pole.
Fig 1. Chopper Amplifier and Chopper OP
The ac and pac simulation results for the opamp open-loop responses are given below.
Opamp (AC): DC Gain = 100 dB
Chopping frequency: 1 MHz
Opamp (PAC): DC Gain = 25.7 dB (Expecting 64 dB)
Could you please show me where I have done wrong?
Thank you very much
