MCU stuck - when reach high temp, about 85C

[OrenS]

Hello,

In our application there is a STM32L073CZT3 component, we use timers and DMA to generate PWM that simulates a sine wave to start a motor.
We encounter a problem with the microcontroller at high temperatures (about 80 degrees Celsius and above).
The microcontroller stuck in all sorts of different states, sometimes the DMA and timers continue to work but the communication and control(PID) stop running in the background, sometimes everything stops (the external clock continues to work at 24MHz), and sometimes the DMA interrupts stop working for a few milliseconds (1-7msec)  and then start working again (which produces a reset in our case as a result of a return current from the motor, and a protection component that disconnects power to the circuit).

Can you help with ideas why this is happening to us?

Thanks,
Oren Shoef.

[Ozone]

> In our application there is a STM32L073CZT3 component, we use timers and DMA to generate PWM that simulates a sine wave to start a motor.

I suppose you have a serious EMI problem in your board / application. Inductive loads require significant protective measures.

> We encounter a problem with the microcontroller at high temperatures (about 80 degrees Celsius and above).
This is usually caused by protective circuitry on MCU GPIOs being blown.
Most likely, you can scrap the board.