My STM32 device is overheating and has malfunctioned

[Wadeva]

Hello,

We’ve designed a device that uses an STM32 microcontroller to manage various features such as I2C, UART, ADC, IWDG, DMA, Flash memory handling etc. After running smoothly for a month, the device began malfunctioning, drawing 220 mA of current and heating up noticeably. I’m trying to determine the root cause of this issue. Could you provide insights into the possible reasons for this behavior?

Thank you.

[Andrew Neil]

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@Wadeva wrote:

Could you provide insights into the possible reasons for this behavior?

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1. A hardware failure in your external hardware
2. A design error (software and/or hardware) over-stressing the part (or allowing it to get over-stressed).

For anything more specific, you're going to have to give a lot more detail!

[Wadeva]

Dear Andrew,

Our design involves numerous components, making it difficult to specify each one. We are using the STM32G070CBT microcontroller.

I’m unsure what might be causing this issue, as all peripherals and features seem to be functioning normally—no signs of overcurrent or short circuits. However, I’m curious if this type of malfunction could be related to something specific, like overcurrent in a peripheral or excessive heat.

I will try to narrow down the issue by individually testing each peripheral and reviewing our software.

[Andrew Neil]

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@Wadeva wrote:

Our design involves numerous components, making it difficult to specify each one.

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Your design should fully specify all of them!

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@Wadeva wrote:

I’m curious if this type of malfunction could be related to something specific, like overcurrent in a peripheral or excessive heat.

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Yes - as I said, over-stressing the part.

The primary result of overcurrent is overheating!

[TDK]

Look for possible places where the chip might have been overstressed, perhaps on powerup, perhaps by an external component through a long (inductive) wire, or ESD damage, or something of the sort.

When the chip is overstressed, the protection diodes can fail and cause the chip to sink a massive amount of current, sometimes while otherwise working okay.

[White_Fox]

How do you have your output pins configured?

Just try to config all as open drain with pull-up, be carefully that e.g. pwm stages may stop working correctly. If all pins are going high, you can exclude that your periphery is broken.

Next tests and other cases are more difficult, but also more rare I guess.

[Tesla DeLorean]

If you have connected to external equipment, boards or circuits, and have insufficient protection on-to the STM32.

Things like motors. Things with their own independent power sources.

Or where you've created conduction paths running through the MCU.

[Wadeva]

Thank you TDK.

I will look and search with my team and tell you if we found the main reason.

[Wadeva]

We are using both push-pull and open-drain configurations on different pins. Additionally, some pins have internal pull-up or pull-down resistors activated.

An interesting test. I will give it a try but as you said my problem might be the rare one.

[Wadeva]

As you mentioned, our design includes external devices. Thank you for all the responses. If we identify the root cause, I will provide an update here.