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Original question:

CSD25480F3 Vgs positive threshold?

CSD25480F3: Gate current through ESD diode forward biased

Peter Schiller
Prodigy 30 points
Part Number: CSD25480F3

The CSD25480F3 includes integrated ESD diode on the gate so positive gate voltage relative to source is clamped.  Has this part been evaluated for latch threshold for VG>VS, and if so, how much positive gate current is safe?  Are there buried junctions or twin wells that might create parasitic BJTs?  Thanks in advance.

  • 0
    TI__Expert 7905 points

    Peter,

    Thanks for considering our FETs.

    I am checking with some colleagues and someone will get back to you tomorrow with an update.

  • 0 in reply to Chris Bull
    TI__Mastermind 38010 points

    Hi Peter,

    Thanks for the questions. See response below from my colleague.

    The diffused diode under the gate is a very simple, vertical P-N diode whose doping concentration is adjusted to provide the desired clamping voltage – in this case about 14V.  There are no nearby junctions that would lead to significant parasitic bipolar action and the device is terminated with a field plate to prevent breakdown at the surface of the device.  This clamp diode is routinely tested at 1mA with no adverse effects.  We do advise minimizing the current in clamping mode (in breakdown) to perhaps 35mA to minimize adverse thermal effects, with the actual current limit determined by the thermal time constant of the system in application.  This clamping diode has a proven track record of providing excellent ESD protection and should prove to be robust in typical load switch applications.

    I’ve not personally tested this particular 14V diode, but have tested the 6V derivatives in the 232xx series, by pulsing them over weekends of time at up to several amps of current without ANY degradation in the measured IV curves.  This vertical diode is a solid performer.

     

  • 0 in reply to John Wallace1
    Prodigy 30 points

    Thank you Chris and John.  This is very helpful.  Just to confirm, is the 1mA at which these devices are routinely measured Forward current in the gate ESD diode, or is it Reverse current?  Our application will stay well below 1mA of forward current.  Is the 1mA forward(?) current through the gate ESD diode part of production test (100% tested)?

  • 0 in reply to Peter Schiller
    TI__Mastermind 38010 points

    Hi Peter,

    I'm checking and will get back to you as soon as I have a response.

  • 0 in reply to John Wallace1
    TI__Mastermind 38010 points

    Hi Peter,

    Thanks again for your interest in TI MOSFETs. I checked with the team and the ESD diode is 100% tested with 1.0mA current in both the forward and reverse direction. The zener breakdown voltage and forward voltage are measured during these tests.

  • 0 in reply to John Wallace1
    Prodigy 30 points

    John - excellent.  Thank you very much!