STM32L422 High current consumption in STOP 2 mode

[ZPapa.1]

Hello,

We are trying to put an STM32L422 MCU to STOP 2 mode but the pcb consumption is high (~60uA). The PCB is not to blame because when the MCU enters STANDBY mode, the current consumption is ~5uA.

In order to set up the MCU to enter STOP 2 mode, we followed the example \STM32Cube_FW_L4_V1.16.0\Projects\NUCLEO-L412KB\Examples\PWR\PWR_STOP2.

The only peripherals that we need to remain active are an interrupt in PA1 and the RTC.

[Mohamed Aymen HZAMI]

Hello @ZPapa.1​,

The current consumption in standby at 3v without RTC and independent watch dog is 120 nA not 5µA as you said, so in this case you need to check your pcb or maybe you miss something in the code.

Mohamed Aymen.

[ZPapa.1]

Dear Mohamed,

Thank you for your reply. I failed to mention that the PCB has additional components and modules (e.g Magnetic Sensor) which bring the total current consumption of the PCB at 5uA when the MCU is in standby mode. This number is expected.

I managed to solve the issue. The PA1 pin, which is used as interrupt pin to wake the MCU from STOP 2 mode, had to be pulled down. After pulling down the pin, the PCB current consumption fell to expected levels (around 6uA).

Zissis