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TMS320F2812: TMS320F2812PGFQ

Venkata Siva Prasad Satelli
Prodigy 50 points

Part Number: TMS320F2812

Hi,

I am working TMS320F2812 MCU for my pmsm drive. I am facing problem with 3.3V and 1.8V. After testing of some days the micro controller got spoiled. When I checked the resistance between 3.3V and digital ground, it is showing as short. And it is also short with 1.8V and ground. After replacing the F2812 micro controller with new one, it is working fine. when I powered up my control board without micro controller(not stuffed), all other ICs ( example: 3.3V and 1.8V LDO Regulator) are working fine.

Would you please tell me what are the possible cases for the micro controller failure with the above mentioned scenario?

I am using following IC for the generation of 3.3V and 1.8V from 5V supply.

TPS767D318 - 3.3V

TPS73219DBVR - 1.8V

Thanks & Regards,

Siva. 

  • 0
    TI__Guru* 82910 points

    The most typical cause of a device damaged as you have described is an over voltage event on one of the device pin(s).  The device has built in ESD protection diodes on all GPIOs as well as ADC inputs.  If there is electrical over-stress for enough time and/or at enough of a potential above VDDIO/VDDA it will eventually break down the gate oxide of the device and short power to ground.  

    You can manually check pin by pin to also see if there are pin(s) shorted to VDDIO or VSS.  This would give you an indication of where the event occurred and hopefully you could debug if you have a connection to that pin(s) that needs to be monitored for this condition.

    Keep in mind, apply voltage to the device pins before the MCU is powered also violates this condition, so you also need to be mindful of voltages that are not on the same power domain and that remain "on" even when the MCU is off.  Analog inputs are often the culprit here, since they typically come from a different device power domain.

    The alternative to observing proper power up/down between domains would be to put external clamping diodes that would limit the voltage passed, or some buffer with an enable pin that could control the voltage the MCU sees.

    Best,

    Matthew