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  1. #1
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    A fundamental question about VGA/PGA design

    hello there,
    why constant bandwidth across the gain range is required in VGA/PGA design, what if the bandwidths of different gain settings are different ? Is there a fundamental principle behind this, any comment is welcome.

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  2. #2
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    Re: A fundamental question about VGA/PGA design

    In VGA, it is necessary to have a settling time that is independent of the input amplitude inorder to complete the VGA operation optimally w.r.t time. Suppose if it is not followed, when the amplitude is smaller, the required gain will be high and a constant gain bandwidth would take long time before the next block can process the signal.



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  3. #3
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    Re: A fundamental question about VGA/PGA design

    Yes,

    In VGA/PGA output settling time should be independent of input amplitude.

    Bye.



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