comparator bandwidth calculation

[lhlblue]

in normal case, comparator is used in open-loop, not in closed-loop as feedback-amplifier, so, how to decide the -3db bandwidth of open-loop comparator? is there some formula or guide for the -3db bandwidth calculation of open-loop comparator?
thanks.

 

[erikl]

Like any opAmp, a comparator exhibits a bandwidth limitation characterized by its dominant pole, which in most cases is its output pole. Hence its "built in" 3db bandwidth is approximately 1/2πRC , R being its output impedance, C its load capacitance.