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LM26420-Q1: LM26420 fail tem test

Imelda Zhang
Expert 4725 points
Part Number: LM26420-Q1

Thanks for your support

After the chip returned to normal temperature after a low temperature test, the chip failed.

The output voltage is less than 100mV.

The resistance between sw to GND is 5 ohm.

We guess the lower MOS is short to GND.

  • 0
    TI__Expert 7605 points

    Hi Imelda,

    Thanks for your question.

    From your observations it does seem that the low side transistor is shorted to GND.

    I have some additional questions to better clarify this issue.

    - Is this problem happening on both outputs, or only for output 1 (while output 2 keeps working)?

    - Have they had the same problem with more boards/ICs?

    - I would advise to check what is the maximum voltage value on the SW node during operation. Could you please send a screenshot of the SW node (and its maximum value)? Does this value change at low temperature?

    Thanks,

    Stefano