VCC AND GROUND PINS (59,60) AND (83,82) BURNED WHILE RUNNING(208 pin controller).

[KN.2]

Hi everyone

we are developing simple iot gteway with reference of STM32F746 discovery board schematic.we have done assembling of controller sdram,norflash,rs232,usb2.0 sections one by one after testing with test codes.for ethernet we are using ksz8863 after assembling the ethernet transceiver i got random reset(reset pin oscillation) so i just removed the ic and test again i got the same issue,i removed usb 2.0 transceiver also bcz it shares the same reset pin of micro controller.still the issue is there,i verified the RCC_CSR registers the cause is ecternal pin reset,so i isolate the reset pin by cutting the pcb track near the controller reset pin.then the pin goes high and again tested with RCC_CSR register read program to verify the cause of reset,in this i got 2 times external reset.suddenly got smoke at vcc and and ground pins which i mentioned above.now getting short beteween vcc nd ground.what is the cause of this and how to solve this issue,kindly give the solution.

[Tesla DeLorean]

Sounds like you need to do a serious design review to understand how you're conducting so much current through your IC.

Is this a two layer PCB? How much current do you measure on working boards, and over time?

Double check the netlist, understand the power domains. Make sure you're not using the IC as a conduction path.

Check the the VCAP capacitors are not defective, incorrectly placed or shorted.

Check the external interfaces, any where you could introduce very high potentials?

[Viktor POHORELY]

Are all the supply pads well connected to the supply ring? Even after the cutting of the NRST line?