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AM3359 burned instantly on power up

jerry huang
Prodigy 90 points
Other Parts Discussed in Thread: AM3359, TPS65910


The AM3359 is powered by TPS65910AA1, the input voltage is 5V. When the power is supplied through a current meter, everything is OK, the board can work without problem. But with the current meter removed, AM3359 will burn out on power up. The VDDSHV(3.3V power path) pins will short to ground, AM3359 is totally damaged. I have double checked the input and output of TPS65910AA1, there is no problem found. I have tried 5 times, with current meter installed, everything is OK, removed, AM3359 burned instantly on power up. Does anyone have any troubleshooting tips for the problem? Any suggestion would be appreciated.

  • 0
    Prodigy 90 points

    I removed AM3359 from the board, found the short-to-ground pins are G14 F14 E13 E12 E11 E10 P6 P5 N5, VDDSHV6.

  • 0 in reply to jerry huang
    TI__Guru 62855 points

    Are you inserting the current meter in the 5 volt supply sourcing the TPS65910 or the 3.3 volt supply sourcing VDDSHV6?

    You should verify all AM3359 pins do not have a voltage source applied that exceeds the value recommended in the data sheet.

    For example, all IO pins associated with VDDSHV6 should be within the Absolute Maximum parameter “Steady State Max. Voltage at all IO pins” which is defined to be “-0.5V to IO supply voltage + 0.3 V”.  This requirement also applies before and during power supply ramps.  Make sure you do not have another component sourcing one of the IO pins associated with VDDSHV6 from another power supply that is applied before VDDSHV6.

    Also check all IO pins associated with VDDSHV6 to make sure the Absolute Maximum parameter “Transient Overshoot / Undershoot specification at IO terminal” which is defined to be “25% of corresponding IO supply voltage for up to 30% of signal period” is not being violated.

    Regards,
    Paul

  • 0 in reply to peaves
    Prodigy 90 points

    Thanks for the reply.

    The current meter is inserted in the 5 volt power supply.

    I have solved the problem, the 3.3V power path of my circuit consumes 500mA, and the VAUX2 of TPS65910 can only supply 150mA.

    After change the power supply of some chips to another GPIO controled 3.3V LDO, the problem disapears.

    I still can't figure out the root cause of the instantly burn out on power up.  Why the circuit works when the current meter is inserted?