High speed zener diode?

Discussion in 'General Electronics Chat' started by Shocker33, Aug 26, 2015.

  1. Shocker33

    Thread Starter New Member

    Oct 28, 2013
    14
    0
    Hi,

    I'm looking for a high speed zener diode. One that is capable of operating at hundreds of megahertz.

    Are such devices available?
    If so, which manufacturers and model ranges should i be looking at?


    Thanks
     
  2. nsaspook

    AAC Fanatic!

    Aug 27, 2009
    2,912
    2,177
    Why? A reversed biased Zener diode is a high capacitative device and due to the doping needed for true Zener tunneling the breakdown is slow and noisy.
     
    Last edited: Aug 26, 2015
  3. Shocker33

    Thread Starter New Member

    Oct 28, 2013
    14
    0
    Because i want to build the application circuit found on the datasheet of this device http://ww1.microchip.com/downloads/en/DeviceDoc/md1820.pdf but with faster devices, so i can operate it at a higher frequency.

    The zener and resistor shown in the MOSFET devices aren't in normal MOSFET devices. I imagine that the zeners are there for a good reason, most likely protection, and so i want include them.

    Do you have a source for that nugget of knowledge nsaspook? How slow are we talking?
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,052
    3,244
    What zeners? :confused:
    The only ones I see are inside the MOSFETs.
     
  5. nsaspook

    AAC Fanatic!

    Aug 27, 2009
    2,912
    2,177
    The input capacitance Ciss of the device (TC6320) ranges from 110 to 200pf at 1mhz. The depletion zone for a Zener must be very thin so there can be quantum mechanical tunneling across the barrier so it is heavily doped at high energy. This results in a high charge density and high junction capacitance across the zone that changes with the applied voltage. This junction capacitance and circuit impedance limits the breakdown speed of the Zener as it looks like a short with high speed signals.
     
    MHDS and Roderick Young like this.
Loading...