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    Setting Voltage refrence for MAX9691 Voltage comparator

    Hi Guys,


    I am trying to use voltage comparator MAX9691 in my design. Basically the input signal is sinusoidal with peak of 200mV. So, I want to wire up this comparator in order to detect the pulse when it exceeds 20mV. The IC is 8-pins and very simple but I don't know how to set the reference voltage or the threshold voltage in this IC correctly.

    Thanks
    -M

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    Re: Setting Voltage refrence for MAX9691 Voltage comparator

    There are no built in references so you would have to set it externally with a resistor divider.

    This comparator expects 50 Ohm terminations since it exceptionally fast with +5/-5.2V.

    Alternatively, you can use +/-20mV hysteresis to square up the sine wave. But if you want to PEAK detect the presence of a signal > 20mV then you need a peak detector cct. then a comparator cct.
    A best design is easily achieved with good test specs™
    A better question deserves a better answer. ™
    ... so include all your acceptance criteria ( values, % tolerance) and assumptions in your question or any design.

    ... Tony Stewart EE since 1975
    - slightly north of Toronto



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  3. #3
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    Re: Setting Voltage refrence for MAX9691 Voltage comparator

    Thanks for your response,

    But I am still confused about something. In the datasheet there is circuit example (Figure 1. Regenerative Feedback—High-Speed Receiver with 50Ω Input and Output Termination). This example has VT = -2V. Is VT here the Threshold voltage ? and if yes does it mean if I can manage to do voltage divider as you mentioned with 20mV and connected to VT. The comparator should detect the pulse when it reaches 20mV

    Am I correct or missing something ?

    Thanks
    -M



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