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TPS65381A-Q1: What is the behaviour of TPS65381 when VCCCORE and VCCIO shorted together

user5311130
Intellectual 400 points
Part Number: TPS65381A-Q1

Hello,

We are having an issue that VCC_IO and VCC_CORE pins are shorted at the MCU side. TPS65381 at the VCCIO output pin there is 2.3V which is supposed to be 3.3V WE tried to separate the shorted pins but the output voltage of VCCIO is still below 3.3V How can we overcome this problem?

Thanks for any help

Best.

  • 0
    TI__Genius 12735 points

    Hello,

    Can you clarify which LDO on TPS65381A-Q1 is supplying VCC_IO and VCC_CORE? If there are two regulators being shorted together then damage is possible. Have you tried replacing the device on the board after removing the short?

    Best regards,

    Layne J

  • 0 in reply to Layne J
    Intellectual 400 points

    VCC core is supplied from SDN6pin with a N mos as the reference design and VCCIO is supplied from VDD3/5 pin with 3.3V configuration

    Have you tried replacing the device on the board after removing the short?

    Yes we replaced the part after the short but the problem still exists

  • 0 in reply to user5311130
    TI__Genius 12735 points

    Hello,

    Do you have a schematic you can provide or can you point me to which reference design you are referencing? VDD3/5 should only be outputting at 3.3V so unless the short is still present or the PMIC is damaged VDD3/5 should be operating normally. I would check to confirm that no other MCU pins have shorts.

    Best regards,

    Layne J

  • 0 in reply to Layne J
    Intellectual 400 points

    schematic can be found above. Many thanks

  • 0 in reply to user5311130
    TI__Genius 12735 points

    Hello,

    Is it possible to disconnect either VDD1 or VDD3/5 from the MCU to confirm that the regulators output correct when not connected to the MCU? I am trying to help determine if there is still a short somewhere causing the voltage change. Can you also provide a scope shot of VDD3/5 and VDD1 output voltage during device startup?

    Best regards,

    Layne J