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LM2576HV: Damaged IC's coming back from the field

Michael Browning
Prodigy 210 points
Part Number: LM2576HV
Other Parts Discussed in Thread: LM2576

In the past 4 weeks, we have had about 20 boards come back with the LM2576HVS-ADJ IC blown as seen in the photos above. This is a part and schematic that we have been using for the past 10+ years with no issues. My current theory is that the input power to the IC rose above the 72VDC limit, but I have no way of proving that is what is going on in the field.

I have put a dead short on the output, exceeded the current rating of the inductor, and tried overheating the IC but none of those tests resulted in a failed IC. The expected load is ~0.75A at the worst case which is well below the LM2576HVS-ADJ and inductor current rating.

  • 0
    TI__Mastermind 22740 points

    Hi Michael,

    Thanks for using the LM2576 in your design, and sorry to hear that you are having troubles suddenly. For the damaged boards, have you been able to send a replacement and see if the same damage behavior repeats itself? Where did you get the ICs from? 

    Meanwhile, can you also provide the layout of the power-supply as well as startup/shutdown waveforms (VIN, OUT, FB) of a good board?

    Regards,

    Richard 

  • 0 in reply to Richard Fu22
    Prodigy 210 points

    Layout of the 24V supply.

    I will work on getting a scope on the signals.

    I have not heard of any repeat failures but the failures have always occurred during normal operations and not start up.

    I am not sure where our board house gets the IC's from.

  • 0 in reply to Michael Browning
    TI__Mastermind 22740 points

    Hi Michael,

    Thanks for the response. I'll take a look at the layout.

    Is it possible to test a sample from the board house (preferably from the same batch as blown boards) and test it in steady-state? It's a bit strange that a design starts failing after a decade..  and may I ask if these failing boards have been in use for a while, or are they new?

    Regards,

    Richard