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TPS62822: IC Short

Kowsalya K
Prodigy 40 points
Part Number: TPS62822

Tool/software:

Hi,

The regulator had a short issue, I checked impedance before power on the board the impedance was in the range, after power on within 5 seconds the PCB was shorted after that the impedance range is 0 to 1 ohm only. After I found the issue in the regulator. So, I changed the regulator with the new one. then also it happens the same short there.

We had 3 PCB boards, 1 PCB didn't have any issue it's working, but the issue occurs in another 2 boards. 

Note: current consumption also with in the value (0.25A), Schematic FYI.

Kindly respond this issue.

Thanks,

Kowsalya K

  • 0
    TI__Genius 15480 points

    Hi Kowsalya,

    Can you probe with an oscilloscope the input voltage close to the VIN and GND pins of the IC during startup to see if there is any overvoltage spike.

    Best regards,

    Varun

  • 0 in reply to Varun John
    Prodigy 40 points

    Hi Varun,

    Recent Calibrated RPS only we are using and there is no overvoltage spike.

    Regards,

    Kowsalya

  • 0 in reply to Kowsalya K
    TI__Genius 15480 points

    Hi Kowsalya,

    Can you take a scope shot of the VIN (probe close to the IC VIN and GND pins) during startup (during the point of damage)? Please also probe the output voltage and SW pin while taking this scope shot. This will help us to understand what happens when the unit gets damaged.

    Best regards,

    Varun

  • 0 in reply to Varun John
    Prodigy 40 points

    Hi Varun,

    2nd Channel blue line is 3V, as you said to probe.

    And we changed to new IC for one Board, the IC didn't short but for another board the IC got shorted, that scope short only i attached. Finally, the root cause of the short is IC.

    Regards,

    Kowsalya

  • 0 in reply to Kowsalya K
    TI__Genius 15480 points

    Hi Kowsalya,

    Thanks for taking the scope shot. This seems to be a scope shot after the device is damaged. I wanted to check a scope shot during the startup process when VIN is ramped from 0V to 5V. Could you kindly capture this scope shot? 

    Do you know if the device is gets damaged during the startup or a little after startup? If this is after startup, can you also try to capture the waveforms (VIN, VOUT, SW) during the damage?

    Best regards,

    Varun