Hi,

I am now workign on a mixed-mode sensor interface IC that requiers a very-low bandwidth filtering (0-0.01Hz).  The sensor is capacitive with a -3dB frequency of 100Hz, so it needs on-chip noise band limitation anyway.

I myself am thinking of using high-order SC filters but there are two main problems:
Large total capacitance and signal fading through the leakage of CMOS switches.

BTW I want to use sigma-delta modulator as well to generate digital output.

Do you have any suggestion how and where I could do the filtering in my circuit?

Thank you,
Babak