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    Comparator - Propagation delay/ Response time Vs. input frequency

    Hi There,

    I am really confused between two parameters in the comparator. The Propagation delay and the Response time.

    I understand that the Propagation delay is the delay from input to output of a digital gate switch and the Response time is how quickly a comparator changes output based on an input change.

    But I don't know which parameter I have to take into consideration when I choose particular comparator given that my input signal has frequency of 500 MHz.

    knowing that not all comparators datasheets provide both parameters value.


    Any Help will be Appreciated :)

    Cheers,
    Mourad

    •   Alt7th April 2014, 08:33

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  2. #2
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    Re: Comparator - Propagation delay/ Response time Vs. input frequency

    Is the 500MHz signal digital or analog (sinewave)? Generally you would want the response/delay time to be less than 1/2 the cycle period or 1ns for a 500MHz signal. That requires a very fast comparator.
    Zapper
    Curmudgeon Elektroniker



    •   Alt7th April 2014, 08:42

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    Re: Comparator - Propagation delay/ Response time Vs. input frequency

    Hi Crutschow,

    Thanks for your reply

    It is an analogue Sine wave. I can not really find any comparator with this high speed.

    Do you know any comparator with this speed or response/delay time ?


    Cheers,
    Mourad



    •   Alt7th April 2014, 08:59

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    Re: Comparator - Propagation delay/ Response time Vs. input frequency

    Quote Originally Posted by MouradR View Post
    I am really confused between two parameters in the comparator. The Propagation delay and the Response time.

    I understand that the Propagation delay is the delay from input to output
    That's correct. Response time, however, is the time, which is necessary for an input signal to stay in an input range, which logically would cause an output change. I.e. the time necessary to accept such change. Usually shorter than the prop. delay time.

    Find very fast comparators in the (M)ECL series.



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    Re: Comparator - Propagation delay/ Response time Vs. input frequency

    Here are some fast comparators.
    Zapper
    Curmudgeon Elektroniker



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