cmos amp design: input is close to ground

[freewing]

The input is close to ground, what type of CMOS amp or comparator can handle this?

 

[dick_freebird]

You are looking for either "rail to rail input" or "input common
mode range includes ground" input features. Anything
from the venerable LM339 to CMOS R-R op amps can do
it, but not all are set up that way.

Searching for things like

rail input "op amp" schematic

or

input common mode ground "op amp" schematic

ought to turn you up plenty of viable hits to study.

 

[jesseyu1984918]

I think you could use PMOS input differential pair and using very small W/L ratio.