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TPS62290-Q1: output is 1.89V and then shutdwon

Amelie Zheng
Genius 10865 points
Part Number: TPS62290-Q1

Hi Team,

Customer now use TPS62290TDRVRQ1 in their design to output 1.8V to power flash but found 5pcs abnormal when testing 40 pcs.

The abnormal is output change from 1.8V to 1.89V; SW impedance to GND change from 10M ohm to 60ohm.

One thing would like to check with you is when 62990 is power-off, customer will add 1.8V to 62990 output directly. Because customer would like to program flash during the test. And then, 1.8V is removed, customer only use 62990 output to power flash.

May I ask whether it will damage 62290 when adding 1.8V to its output though 62290 doesn't power-up?

And whether customer SCH is ok? Any advice?

Here is abnormal one which is 1.87-1.89V output and come into protection because the temp is high.

  • 0
    TI__Expert 7585 points

    Hi Amelie,

    Thanks for your question.

    A change in the SW pin impedance may point towards an overvoltage on the same pin.

    Sometimes even plugging and unplugging the program interface could cause the overvoltage.

    The connection of an output voltage while programming could potentially cause a problem. Can you please share more information on what is connected to the output and input?

    The schematic looks fine to me.

    Could you please clarify the following points?

    • Why is the device overheating in the screenshot? Are you operating at an high ambient temperature or it is only due to the device abnormal behavior?
    • Is any other component damaged in the PCB? (Have you tried to replace the device and check functionality?)

    Thanks,

    Stefano

  • 0 in reply to Stefano Panaro
    TI__Genius 10865 points

    Hi Stefano,

    The output connected to flash power. I am curious. Because during the 62290 output have 1.8V, 62290 didn't power up and have no input. Will this also impact the chip?

    Stefano Panaro said:
    Why is the device overheating in the screenshot? Are you operating at an high ambient temperature or it is only due to the device abnormal behavior?

    It is not at high Ta, it is only due to the device abnormal behavior.

    Stefano Panaro said:
    • Is any other component damaged in the PCB? (Have you tried to replace the device and check functionality?)

    No, customer also do ABA. When change the damage one to good one, it work.

  • 0 in reply to Stefano Panaro
    TI__Genius 10865 points
    Stefano Panaro said:

    A change in the SW pin impedance may point towards an overvoltage on the same pin.

    Which pin have overvoltage?

  • 0 in reply to Amelie Zheng
    TI__Expert 7585 points

    Hi Amelie,

    If the customer applies an output voltage while the input voltage is not supplied, you have a current flowing in the body diode of the high side mosfet that could potentially damage the device.

    A simple solution to avoid this could be to power the buck during programming.

    In the previous message I was referring to an overvoltage on the SW pin.

    Sometimes just plugging in and unplugging programming equipment may cause an overvoltage. 

    Thanks,

    Stefano