STM32U575CGU3: ADC_Init enables analog bias that cannot be disabled by ADC_DeInit?

[k.morohoshi]

Hi,

On STM32U575CGU3, calling MX_ADC1_Init() once increases the device current by about +200 µA. After that, even if I run HAL_ADC_DeInit(), reset ADC1, and disable VddA, the extra +200 µA current does not disappear.

Here is the minimal code:

c

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

    MX_GPIO_Init();
    MX_GPDMA1_Init();
    MX_ADC1_Init();         // <-- Base +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); // <-- This does NOT reduce the +200uA
    __HAL_RCC_ADC1_FORCE_RESET();
    __HAL_RCC_ADC1_RELEASE_RESET();
    HAL_PWREx_DisableVddA();

    while (1) {
        __NOP();
    }
}

Question

Does ADC_Init enable an internal analog bias that cannot be fully disabled by ADC_DeInit, ADC reset, or VddA OFF? Is there any complete shutdown procedure to fully power down ADC/VREFBUF after initialization?

Thanks.

[Saket_Om]

Hello ​@k.morohoshi 

The issue you encounter seems to be related to the errata 2.9.2

Please try to apply one of the workarounds mentioned in the errata.