how to test the input common-mode range of a comparator?

[tommydidi]

The comparator uses pmos input diff pairs. Thanks.

 

[transbrother]

There are many ways of doing this. One way is to monitor the prop delay at different common mode input levels with different ~100 mV (or any) overdrive at the inputs and make sure it doesnt degrade. The other is the monitor the threshold (and thus offset at the transition point) of switching voltage produced at different common mode input levels.

 

[analog_prodigy]

In unity gain feedback toplology plot the input and output and the current through the diff amp

the input voltage till which the output follows, gives you the input common mode range