CMOS threshold detector

Hi,
I am designing a CMOS zero threshold detector. I can only work with a single power supply of 3.3 V in 0.35 micron technology. Now if I give one of the inputs to the comparator as ground i.e 0 V then won't that particular transistor stop working in saturation? How will I get the circuit to work then? Please help me!!!!!

Thank you,
Regards,
Sumera

You have to use a P-channel differential pair if you want your common-mode range to include zero volts. If you also want it to work at Vcm=3.3v, there are techniques you can use which include N-channel and P-channel diff pairs.

Thank you!!!

Thank you for your quick reply. I will try out what you suggested ..

Sumera