Low-power modes for STM32WB5x

MSing.1713 · ‎2020-02-05

Greetings,

We're looking into the low power modes of the STM32WB. Our measured consumption in Stop2 on our custom PCBA is very close to the expected value. However, in reset (holding the reset button), the MCU is not drawing what we'd expect.

For comparison, we put the Nucleo in reset and we find that the current draw is substantially higher than the DS describes. The DS says the MCU should draw no more than 0.75uA while in reset. What we're seeing is 148uA in reset measured at JP3. At JP2, the reset current is 454uA.

We've been powering the board from the user USB header, but we see the same currents when we power the MCU from the ST Link USB header.

We don't see anything in the schematic that would account for this extraordinary difference. Is there something we've missed?

Cheers

Remi QUINTIN · ‎2020-02-11

There is a mistake regarding the unit. It should be nA , not uA. This will be corrected in the next DS version 6.

The max current is 750µA and the typical value is 450 uA. So what you measure is consistent with those values.