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AM335x TPS65217C PMIC issue

Vageesh KM
Expert 1075 points
Other Parts Discussed in Thread: TPS65217

Hi,

TI TPS65217C (single chip PMIC for battery powered system) IC problem ,

we have designed a Sitara processor based board which is powered by TPS65217C IC.

All the on board voltages for DDR, Processor and other devices are generated using  TPS65217C IC.

Couple of months boards worked fine, now we are observing SYS_5V (out put from TPS65217) is falling down to 1.1V instead of 5V,

As SYS_5V is used internally to generate all the remaining voltages , we are not getting any of the out put voltages from TPS65217C.

When I measured the voltages we found CORE and 3V3 voltages are shorted to GND.

Same thing happened with second board also, for this board only 3V3 voltage is showing  short, SYS_5V is again dropped  to 1.1V.

We have done all the possible passives removal like all decaps, resistors, dry solder effects etc which was not helped to remove the shots. 

Now we found that MPU is doing this short and after removing processor from the board issue solved.

Kindly suggest what could be the issue and not sure if i replace the MPU issue exists again.

Regards,

Vageesh K M

  • 0
    TI__Guru**** 393215 points

    Hi Vageesh,

    This kind of failure is usually seen when voltages are applied to the processor I/O pins before the processor power supplies have fully ramped up and stabilized. The AM335X I/O pins are not fail-safe. Please refer to section 5.1, parameter "Steady State Max. Voltage at all IO pins" in the AM335X Datasheet Rev. G. Also check Note 8 below the table.

    My advice is to recheck your design and see if any processor I/O pins have voltages applied to them when the processor is not powered up. Note - USBx_VBUS pins are the only ones that are fail-safe and permit this.