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Visitor II
March 14, 2020
Question

How to test if a MCU is broken?

  • March 14, 2020
  • 3 replies
  • 1657 views

Hi all!

I have developed a PCB with a stm32f4 MCU.

The MCU can be programmed through SWD and works well.

However, the current consumption of the whole PCB is high (~190 mA at 3.3 V). When I erase the chip, the current consumption becomes 120 mA.

Could you recommend what could I do to understand, if the high current leakage is due to the broken MCU or due to problems in other PCB units?

Thank you in advance

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    3 replies

    Graduate II
    March 14, 2020

    Perhaps you could have it tristate different banks of GPIO pins so you can identify areas of the design to focus on.​

    Graduate II
    March 14, 2020

    If you erase the chip, it runs from HSI starting with all peripherals disabled. Then the datasheet shows a Max value of 7 ma. To 120 mA is definite to high and I suggest you consider the MCU broken!

    Super User
    March 15, 2020

    It could be that your mcu is fine and other parts of the board are sinking the 120mA. That seems more likely to me.