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ESD Device to Eliminate Negative Spike on USB 2.0

Jason Liu3
Intellectual 1010 points
Other Parts Discussed in Thread: TPD2E2U06

Hi Team,

My customer found that there is negative voltage spikeon D+/D- of USB2.0 port, its peak is about 0.7V, last ~100ns.

Can ESD device eliminate the negative voltage spike? If yes, please recommend proper part.

Recent USB hub can accept -0.5V as maximum rating, so customer wounder if we can use ESD device to clam the spike below 0.5V negative.

  • 0
    TI__Genius 12190 points
    Hi Jason,

    I recommend TPD2E2U06. It is our most robust ESD protection device and is perfect for protecting the DP/DM data lines of USB 2.O. Not that you need such strong ESD protection for -0.5V for 100 ns, an ESD event has the same transit time, and this device is rated for 25kV.
  • 0 in reply to Guy Yater
    TI__Intellectual 1010 points

    Hi Guy,

    Below is the scope shot of USB signal. Please kindly confirm if  TPD2E2U06 can clamp the undershoot to -0.5V. Thank you very much.

  • 0 in reply to Jason Liu3
    TI__Genius 12190 points
    Hi Jason,

    I see that the negative voltage spike is actually undershoot in the data signal. Since the application goes outside of the design scope, it is too risky to try and use the device to clamp a signal that repeats so often. My concern is that the device would fail under constant clamping. Also, it will not clamp to -0.5 V, it's more of a diode drop of -0.7 V. Based on this more detailed description, I would not recommend an ESD protection device be used to fix the undershoot for a couple of reasons: 1) The constant sinking of current goes beyond the design scope of the TVS, thermal damage may result; 2) The clamping voltage magnitude will exceed 0.5 V - maybe approaching 1 V.

    Regards,