STM32G0 - how to achieve 40nA shutdown current as per documentation?

[Coratron]

Hi I am using an STM32G071 Nucleo board and would like to know if it is possible to achieve the advertised current of 40nA in shutdown mode.

I have no problems entering shutdown mode but the observed current with my nRF PPK2 is closer to 1uA. I have disabled the RTC.

1) Is the current of 40nA possible on the Nucleo board?

2) Are there any required steps before entering shutdown mode?

Thank you

[Sarra.S]

Hello @Coratron​ 

As you know,  In the lowers-power modes, any difference is significant when we're talking about nanoampere

it is advisable to ensure that all of the unused peripherals are disabled in order to further minimize the current drawn. It is also a good idea to disable the 32-kHz external oscillator as it can draw considerable amounts of current in shutdown mode if left active.

Also, Make sure to set all free pin as analog

Hope that helps!

[KDJEM.1 · Accepted solution]

Hi @Coratron​ ,

Please check the parameters mentioned in the DS12232 and precisely in table 31.

To minimize the power consumption in low power mode, I advise you to take a look at How to minimize the power consumption in low power mode: An example using NUCLEO-F401RE board article.

When your question is answered, please close this topic by choosing Select as Best. This will help other users find that answer faster.

Thank you.

Kaouthar

[Coratron]

Thanks @Sarra.S​ I had taken all those measures. It would be nice if there was an official example (for Nucleo?) in STM32CubeMX to showcase it so users would know they have not made a mistake.

@KDJEM.1​ thank you for pointing that out. The variance is significant. It looks like the advertised 40nA is maybe not as "typical" as it is a lucky measurement, it loses its meaning as it can't really be relied on for ultra low power. So at room temperature (25C) it can vary from below 100nA to above 1000nA. It looks like I was doing everything right then and it's just what it is.

Case closed.

[Piranha]

https://community.st.com/s/question/0D53W00001bnh8dSAA/how-to-enter-standby-or-shutdown-mode-on-stm32

[Coratron]

Did you achieve low currents? Not sure it is something that can be relied on from the datasheet.

[Piranha]

Yes, I have achieved it on L43x devices and the currents correspond to the ones in datasheets.

All of the ST's low-power examples are just broken. My article shows how to do it correctly.

[Coratron]

Ok, I think the STM32L family guarantees those currents in some low power mode configurations. Also, what voltage are you using to power the STM32L43x?

[Piranha]

I'm using it with 3,3V provided by MCP1810 regulator. It runs RTC from LSE with ABS07W crystal. And I also use SRAM2 retention with Standby mode. Though I've also used other combinations with a different crystal, no SRAM2 retention and Shutdown mode.

Are you measuring the current at JP3 and no additional connections that could consume the VDD current?

[Coratron]

That's correct, JP3 and nothing attached. I think the current I measured is within spec for the STM32G0. Lowest I got is 690nA.