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LM5101A: can LM5101A support -2.75V between HO and HS pin?

Part Number: LM5101A


in customer's system, LM5101A is used to drive hard switch full bridge MOSFETs

below is the waveform on HO-HS, -2.75V negative voltage can be seen.

customer want to know if  LM5101A  can support this -2.75V? is there any risk to make this chip damaged?


  • Hello Max,
    Thank you for supporting the LM5101A with your customer. I see that the negative voltage spike to -2.75V peak event is over within one scope division which I assume is 20ns per division.
    Can you comment on the probe used to capture this waveform? Since it is HO to HS was this captured with a differential probe?
    The reason I ask, is that there is a negative voltage that has a long duration, even after the negative spike event is over. I am wondering if there is some DC offset in the measurement.
    If the scope waveform is accurate, because of the long duration of the negative voltage of HO below HS, I would recommend a Schottky diode placed close to the driver HO and HS pins. Make sure the diode is low Vf, 1A rated connected to the HO and HS pins with short traces to clamp the negative voltage.
    If there is some suspicion that the negative voltage shown is a measurement offset, please confirm in the measurement setup and provide additional plots.

    Please confirm if this addresses your questions, or you can post additional questions on this thread.
    Richard Herring