Unexpected Current Consumption in STOP2 Mode on STM32U595

[Dadigno]

Hi everyone,

I’m facing an issue with power consumption in STOP2 mode on my custom board.
The board includes only the STM32U595 MCU, bypass and decoupling capacitors, and the inductor for the SMPS — nothing else is connected.

According to the datasheet, I expect a current consumption of around 4.65 µA in STOP2 mode (pag 214 Table 59, VDD = 3.3 V).

However, when I measure it with my STLINK Power Monitor, I get about ~10 µA with fast oscillations.

MX configuration:

• All peripherals are disabled

• SysClk = 16 MHz

• All SRAM banks in Power-Down mode

• Power saving mode enabled

• SMPS enabled

• Voltage scale = Range 4

• All pins configured as analog input (via Project Manager → Code Generator)

Application code:

  HAL_DBGMCU_DisableDBGStopMode();
  HAL_Delay(5000);

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
    printf("Entering lowpower mode\r\n");
    HAL_Delay(500);
    HAL_SuspendTick();
    HAL_PWREx_EnterSTOP2Mode(PWR_STOPENTRY_WFI);
    // HAL_PWREx_EnterSHUTDOWNMode();
  }

Does anyone have an idea what could be causing this higher current consumption in STOP2 mode?
Any suggestions or insights would be greatly appreciated!

[Andrew Neil]

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@Dadigno wrote:

 on my custom board.

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As it's a custom board, you need to show the schematics

How to write your question to maximize your chances to find a solution

Have you tried the ST examples on an ST board for reference?

Have you tried the ST examples on your custom board ?

https://www.st.com/resource/en/application_note/an5701-stm32cube-mcu-package-examples-for-stm32u5-series-stmicroelectronics.pdf#page=11

[Dadigno]

@Andrew Neil 

Thank you for your quick reply.

No, I haven’t been able to test any examples on an ST board yet, but I used the official examples as a reference.

This is my current hardware setup. The board is actually more complex, but at the moment the only components populated are the ones shown in the photo — all other pins are floating.