Power Section problem for Tm4c1294.

Hello Shaheen

Can you share the schematics of the power stage and the micro?

Regards
Amit

Am I making any mistake???

Someone, most probably. These are the woes of prototype design ...

I suggest to trace the important values/lines/pins with a scope (or similar equipment), to identify the source of your problem. To save costs,you might replace the MCU with a resistive load (i.e. resistor) representing the worst-case load for the power supply.

Otherwise (as Amit requested), not much to say without further information, like the schematics.

Hello Amit,

The Schematic is attached.

Kindly look into it.

Schmtc.pdf

Regards,

Shaheen.

Hello Shaheen,

The schematic looks fine except that the number of decoupling caps per VDD/VDDA pin is far less. There should be a 0.1uF per pin and a 10uF bulk capacitor. That should however not be the cause of issue. On the board where the MCU is damaged, if you remove the MCU then does the 3.3V come back up?

Also for a FA you would need to send back the device to TI.

Regards
Amit

Hello Amit,

Ok. I will increase the decoupling caps in the next version of my PCB.
Yes after removing the MCU the short is removed.
I have checked the MCU's VDD and GND after removing it from the board it is internally shorted.
How to send back the IC??
If power section is ok then what may be the cause???

Regards,
Shaheen.

Hello Shaheen

If you have a regional FAE assigned to your organization, then you can ask them to prepare a return form.
Once we look at the damage on the device, we could tell what may have been the cause,

Regards
Amit

Hello Amit,

Till then I have to wait???
Can you suggest some way to trace what may be the cause?

Regards,
Shaheen.

It is not "only & always" that damage stems from/due to the, "Power Section."

Your report is silent wrt any/all (other) voltages/signals which may be introduced to the MCU.   While the MCU has (some) resistance to input signal excess - this cannot (always) be counted upon - thus the safest course is to "prevent" the arrival of such signals.

In addition - how do you know that your System Clock is not excessive - or otherwise "outside" of specification.   An over-clocked MCU may run for the short duration you mention - and then "pass on" to, "after-life."

As always - builds of ONE board - delay & confound test/verify.   Multiple boards reduce (or eliminate) the chance of, "Single Board Anomaly" and should (always) receive high consideration...

Hello Shaheen

Yes. Once the part is received, it takes time for the device to be analyzed for damage.

Regards
Amit