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Narrow pulse width generation

Discussion in 'Electronic Components' started by Tom Sanders, Apr 2, 2004.

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  1. Tom Sanders

    Tom Sanders Guest


    I am trying to use a rising edge of a clock to generate a
    sub-nanosecond pulsewidth. Does anyone know of any components out
    there that can be used to achieve this?

  2. Boris Mohar

    Boris Mohar Guest

    Step recovery diode or SRD.
  3. CBarn24050

    CBarn24050 Guest

    An xor gate will produce a pulse on each edge, width is equal to the time
    difference between the ip pulse to each input. You can add an and gate to
    supress the extra pulse.
  4. mike

    mike Guest

    How sub?
    How big?
    Are you ever gonna need a second one? How soon?

    If you look into the emitter of an emitter follower, you
    can convince yourself that a first order approximation to
    the behavior is a resistor and inductor in parallel.
    If you stuff in a current step, you get a voltage pulse.
    It's amplitude and tempco compatible with the old MECL III logic

    The interesting part of the behavior is that when you turn off
    the current, the (virtual) inductor goes away. Makes a way cool short pulse
    generator without all the nasty ringing properties of a shorted
    transmission line or a real inductor. And if you drive it too fast
    (rep rate) it just becomes sorta transparent. One-port devices are neat.

    For a given state of technology, you can probably get shorter pulses
    than with a gate-delay differientiator.
    I used it at rep rates of 250 MHz. 30 years ago.


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  5. Tom Sanders

    Tom Sanders Guest

    Thanks, I am looking to create a 140-150ps pulse width. Can this be
    done using the XOR and AND gates that you recommended?

    Thanks in advance for your help.

  6. Hal Murray

    Hal Murray Guest

    Thanks, I am looking to create a 140-150ps pulse width. Can this be
    That's pretty exciting. What are you going to do with it?
    What do you use for a buffer/amplifier?

    140 ps is 7 gigabits. You might be able to make that with
    a parallel to serial converter - SERDES. You need one that lets
    you feed in the raw bits rather than doing the 8B/10B type
    encoding for you.

    Xilinx gets up to 3 gigabits in their RocketIO in their Virtex Pro
    family. The Pro X line says 10 gigabits, but I don't think they
    are available yet.

    I took a quick scan at OnSemi's ECLInPS line. It's what I think
    of as the top end of simple gates. They say 3 gigahertz toggle
    freq for the MC100EP08 and a typical rise/fall time of 130 ps.
    So that's off by a factor of 2 from your target.
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