Can the STM32U5 integrated SMPS be used to power external components?

[Terry Greeniaus]

We're planning a design that uses the STM32U5 with built-in SMPS. Our device also uses USB, and the U5 packages we have are ones where VDDUSB is bonded to VDD so we must set VDD = 3.0-3.3V for the USB transceivers to work.

We have other devices on our PCB that can operate at lower voltages to save power and I was wondering if instead of tying them to VDD if we could tie them to the SMPS output (which I think is on VDD11 and I think would be the same voltage as whatever VCORE is configured to in PWR_VOSR - so somewhere around 1V).

Is this a really bad idea? My gut says this might be a really bad idea, but I am wondering if it is possible.

Thanks,

TG

[RBENF.1]

Hello @Terry Greeniaus​,

Your assumption is correct. The built-in SMPS is designed to supply internal load only.

Regards,

Ryan