urgent: chopper stabilized amplifier's amplifier stage does not work

Thread Starter


Joined Mar 10, 2007
Hi All
I am trying to design a chopper stabilized circuit like Fig4 a) of the attached article "A CMOS Chopper Amplifier"

I can get the input modulator to work but after I attach the opamp, I get a "timestep too small" error message. I tried changing the end time to a big number, but it doesn't fix the problem either:(

I use multisim for my simulation and my circuit is shown in the attached word doc.

If any of you can help me with my problem and have multsim, I will attach a copy of my multisim file to my next posting.

Can someone please give me some assistant

Thanks in advance for your help



Joined Jun 4, 2007
It looks to me that the sim prog can't handle your speed, can you reduce the "clock" frequency to say 1/100 (10Hz)and see if it'll work then?