How does one simulate input offset of chopper amplifier?

[deba_fire]

I have configured the chopper amplifier with a gain of 50.My chopping frequency is 5KHz.I am running a transient analysis for 1ms and then taking the average of the output after the demodulator.Is this method correct?I am getting an offset of 30uV.

I have read on net that chopper offset can be measured using PSS and its more accurate.Here is what I am doing to set PSS.The beat frequency is 5KHz as thats the chopper frequency and I have tied the inputs to common mode.I have set the number of harmonics to zero as offset can only occur at DC.Is this method correct?I am getting an offset of 30uV with this setting.

Can someone please help me with my understanding?

 

[leo_o2]

I think the averaging method is reasonable. However you should take mismatching in your simulation.

 

[deba_fire]

Hi Leo_02
I am doing monte carlo analysis.So my method is correct.Thanks.

My next question
But in practical measurement we will be having a low pass filter at the output after the demodulator.Then if we measure the peak-peak ripple at the output that would give us the offset.Is it right?

 

[deba_fire]

Do you have any comment about the PSS method for simulating offset of chopper amplifier?