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CSD95492QVM: What is the clamping diode avalanche voltage and power dissipation specification?

Beam Lan
Prodigy 20 points
Part Number: CSD95492QVM

NexFET has unique clamping diode to reduce switch node voltage.

What is the avalanche voltage for the clamping diode?

Is there power dissipation limit for the clamping diode?

  • 0
    TI__Mastermind 24075 points

    Hi Beam, 

    We will check and reply to you. 

    Thanks

    Qian

  • 0
    TI__Intellectual 800 points

    Beam,

    CSD95492QVM device has an internal clamping voltage set at 21V typic, min 20.7V.

    Clamping voltage goes up to 23V based on die temperature. Clamping voltage has a 20mV/degC temperature coefficient.

    It's not a discrete diode so you can have power dissipation limit on it. In application, total Power dissipation on switching FET and clamp diode should not exceed 6W limit.

    Best regards,

    Lucian

  • 0 in reply to Lucian Hriscu
    Prodigy 20 points

    Thank you, Lucian,

    Since the "Ask a related question" button doesn't work, I add the related question in reply.

    The question is:

    The LS FET clamping diode remove the charges accumulated during switching dead time. Because the clamping voltage is 20.7V or higher, does that mean when SW node peak voltage is below 20.7V doesn't require clamping diode to remove the charge?

  • 0 in reply to Beam Lan
    TI__Intellectual 800 points

    Beam,

    Not exactly. There are parasitic inductance (pcb and package) present in the FET commutation loop. When HS FET turns ON, output inductor current needs to comutate from LS FET body diode (in conduction during Dead time) to HS FET channel. As a result of current commutation, voltage ringing across LS FET is being generated. If ringing voltage exceeds the diode clamping threshold,  it will be clamped at 20.7V through the diode.

    At light load or in DCM mode the current is low . As such, if voltage ringing is below the diode's clamping  threshold the diode won't be activated. As a result, no power dissipation due to diode clamping will occur.

    Best regards,

    Lucian