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Limiter vs. Comparator

Question asked by Kevin.G Employee on Mar 8, 2010
Latest reply on Mar 10, 2010 by Kevin.G

I'm interested in turning a sine wave into a square wave to get phase/frequency information.  Is there any benefit to using the limiter output of a logarithmic amplifier like the AD8309 instead of using a comparator?

 

The way I'm thinking about it, the limiter output is no different than using an op-amp open-loop, in which case there are several ADI articles discussing using op-amps as comparators.  Most of them, if I recall, suggest against it.

 

Tutorial MT-084: Using Op Amps As Comparators

Application Note AN-849: Using Op Amps as Comparators

Ask the Applications Engineer 31: Amplifiers as Comparators?

Rarely Asked Question: Comparators & Op Amps – May They Never Meet (Or Good Advice From Mr. Punch)

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