lunren wrote on Dec 4th, 2011, 3:28pm:Hi,
I recently saw several cases in which a miller compensated amp is used as comparator. I think there are some difference in terms of PSR, noise and speed between with and without miller compensation cap. But I don's think in these applications, noise, PSR is critical (supply monitor). Then in my opinion, the miller compensated amp is just making the circuit to response slowly, but this doesn't seem a advantage. I am wondering what's the advantage to use miller compensated amp as a comparator?
Lunren, I agree cause you are right.
You
can use a frequency-compensated opamp as comparator - however, the compensation lowers the slew rate and, thus, the response time.
For stability reasons (tendency to oscillation) it is NOT necessary to use such a compensation scheme since there is no operational point within the linear part of the transfer characteristic.