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lhlbluesky_lhl Senior Member Offline Posts: 115	comparator bandwidth Mar 22^nd, 2013, 4:43am 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.
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wave Senior Member Offline Posts: 117 Silicon Valley	Re: comparator bandwidth Reply #1 - Mar 22^nd, 2013, 10:31am Why not look at Propagation Delay instead?
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loose-electron Senior Fellow Offline Best Design Tool = Capable Designers Posts: 1638 San Diego California	Re: comparator bandwidth Reply #2 - Mar 22^nd, 2013, 4:39pm You are trying to determine the BW of a non linear device. That doesn't really make sense. BW for a linerar device, yes, but comparators are typically characterized as a function of propagation delay or response time characteristics.
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raja.cedt Senior Fellow Offline Posts: 1516 Germany	Re: comparator bandwidth Reply #3 - Mar 23^rd, 2013, 2:28am Hello, in addition to jerry comments, there is lot to estimate for sampler and on the top of that bandwidth doesn't make scene much. Have a look at this paps 1. Time Resolution of NMOS Sampling Switches Used on Low-Swing Signals 2.Characterizing Sampling Aperture of Clocked Comparators Have fun, Raj,
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weber8722

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Posts: 95

Re: comparator bandwidth vs Propagation Delay
Reply #4 - Apr 11^th, 2013, 4:56am

Hi,

best check the delay for different input overdrive, e.g. have one input at 1V and the other with puls from a=0.9V to b=1.05V. Then vary both a and b in a loop. You will see that the delay becomes shorter for large b and large a!!
So there is no single number which describes such highly nonlinear circuit as a comparator.
Also there are different parts in response time: like pure delay (to get out of saturation, then a part for rise or fall time.

Bye Stephan

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