STM32F443 NUCLEO-64 Burned MCU

[Carlo Agrusti]

HI all,

while testing the last firmware modification for our project, the MCU suddenly stopped working becoming very hot. The board was powered by a 3-cell Li-ion battery through the VIN pin, and it kept working for several days in this configuration before failure. Post mortem analysis reveals a dead LD1117 voltage regulator, and it seems that its failure caused the MPU burning but it's unclear how it happened.

Any clue on this issue?

[Uwe Bonnes]

If only the CPU had high curent draw I would suspect an accidental short between LIPO Power and some CPU pin. Something similar happened to me several times... However the LD1117 failure is not clear for that reason.

[Carlo Agrusti]

Thank you for your answer, Uwe. Yes, I think you are right - we discovered a stray cable connected to a GPIO that could eventually have hit the LiPo power: now if powered through the ST_Link the MPU drains 500mA. The strange thing is that the LD1117 has burned while the LD39050 is still working properly at its maximum current.