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LM5101A: Reliability concern if slight over-voltage applied to pin 6 on the negative side?

Part Number: LM5101A

From my customer who is qualifying this device for their new project:

Engineering team found that the voltage applied to pin 6 is being exceeded on the negative side slightly:


“During routine testing, an over-voltage on this driver IC’s Li pin6 at -587mV was found, and it exceeds the datasheet’s absolute maximum limit of -0.3V for this pin.  The voltage glitch is caused by the device output changing state about 30ns after the input changes state. It is feed-back from the output to input."

Can we comment on any potential reliability impact from this?

  • Hello Al,

    Thank you for helping support our device in your customer's system.

    Your customer is correct, the -587mV on the input puts the LM5101A outside the absolute maximum ratings which TI cannot guarantee the reliability or operation of the part.

    However, how are you measuring the voltage at pin 6? Using pigtails and measuring close to the pins should reduce any coupled noise and could improve your measurement.

    How long does the negative pulse last for? Does it occur cycle-by-cycle?

  • Hi Al,

    How were you able to solve the negative input spike? I will close this thread if your problem is solved, however you can reopen it if further questions on this issue persist.