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Original question:

TPS22992: Corrupted by unknown cause

TPS22992: Corruption by unknown cause on running

TerryU
Prodigy 145 points
Part Number: TPS22992

Hi experts,

Once I asked about TPS22992 corruption. Although I have not resulted in the cause, I thought that possibility of assembly issue would be high.

However it occurred again on the one of part replacing board, The board ran without failure at first, then it would not be assembly issue. I attach whole of this line circuit diagram. The both of input and output are connected the external connectors. It might be any damage from/to those connectors. However it shall be applied 5V maximum on those connectors.

20240205circuit.xlsx

And I checked this failed board. This waveform indicates PG (CH1) and  5VEN (CH2). There is no VOUT output. I wonder that PG is earlier than 5VEN. Is it also malfunction?

Best regards,

Tetsuya

  • +1
    Prodigy 145 points

    I have noticed on TPS22992EVM, Evaluation board, circuit that it mounted TVS diode at the both of input and output ports. Is it prefer to equip such protection devices for the external connectors?

    Best regards,

    Tetsuya

  • +1 in reply to TerryU
    TI__Mastermind 27900 points

    Hi Tetsuya-san,

    Whether TVS diodes are required is based on the application. In the thread you mentioned that the input and output are connected to connectors - do the cables connected have significant inductance? If you unplug either cable (does it unplug from the load side or TPS22992-board side?) or disable the device, is there any ringing on the input or output?

    Also, I recommend you replace R25 with a 0Ohm or 10Ohm resistor for future builds, as it does not specifically need an inrush resistor.

    Thanks,

    Patrick

  • +1 in reply to Patrick Shalton
    Prodigy 145 points

    Hi Patrick,

    Thank you very much.

    I checked our test equipment, and I found a regulator module in one of our equipment 20ns-short pulse at power on. It sometimes exceeded -2V and it is over  for absolute maximum ratings, -0.3V, of Vin and Vbias . I think, it repeatedly applied for the device, and accumulated damage, then broke.

    Of course I will never use the test equipment, and will add some protection components.

    Regarding R25, it consist some timing circuit, so it cannot change.

    Regards,

    Tetsuya

  • +1 in reply to TerryU
    TI__Mastermind 27900 points

    Hi Tetsuya-san,

    Yes, that sounds like it would violently damage the device like you showed - I'm glad you found this.

    Understood on R25, I don't think this is an issue then.

    Please let me know if you still find that the devices fail, or if you have any questions about this or anything else in the future.

    Thanks,

    Patrick