Hi,

I built a simple class-A amp with 2 stages, and each stage has its own CMFB. I am suprised to see that the output settles to the
maximum accuracy even when I go on reducing the time available for settling. It looks very good of course, but can someone
suggest why this might be happening?

Thanks
Vivek

Hi Tosei,

It seems to only be the differential output. Unfortunately, I cannot post a drawing on my circuit because
I would get into trouble if I did that. However, I can describe the architecture.

2-stages, first stage with NMOS input, NMOS cascode. Compensation cap returns to cascode node.
Switched-cap CMFB for both stages separately so that compensation is simpler. This scheme has been
around in many different forms, and although I have added a CMFB in each stage, I believe that people have
also done this.

I will see if I can find out something from my side.

Regards
Vivek