STM32U575CGU3: Does ADC_Init leave analog bias active? Looking for others who observed similar current increase

[k.morohoshi]

Hi,

On STM32U575CGU3, I see a reproducible +200 µA increase in current after calling MX_ADC1_Init() once. Even after HAL_ADC_DeInit(), ADC reset, and disabling VddA, the additional current does not return to the original baseline.

Here is the minimal code:

c

int main(void)
{
    HAL_Init();
    SystemClock_Config();

    MX_GPIO_Init();
    MX_GPDMA1_Init();
    MX_ADC1_Init();         // +200uA increase
    MX_OCTOSPI1_Init();
    MX_SPI1_Init();
    MX_USB_OTG_FS_PCD_Init();
    MX_USART1_UART_Init();
    MX_ICACHE_Init();

    // ADC Disable
    HAL_ADC_DeInit(&hadc1);
    __HAL_RCC_ADC1_FORCE_RESET();
    __HAL_RCC_ADC1_RELEASE_RESET();
    HAL_PWREx_DisableVddA();

    while (1) {
        __NOP();
    }
}

Questions

• Has anyone observed similar behavior on U5 devices (ADC bias or VREFBUF staying active after initialization)?

• Are there known conditions where ADC/VREFBUF analog blocks remain powered even after DeInit and VddA OFF?

• Any hints on additional steps required to fully shut down the analog domain?

Thanks.

[KDJEM.1]

Hello ​@k.morohoshi ;

 

 Can you check and share which ADC kernel clock source STM32CubeMX generated for ADC on your project?

I recommend you to use HCLK clock source.

 

Thank you.

Kaouthar