Powering STM32WLE5CCU6 without RF

[B5773]

Hi,

I’m designing a PCB with the STM32WLE5CCU6. I don’t plan to use the integrated RF (LoRa) section, but the MCU choice is fixed.

I couldn’t find clear guidance in the datasheet on how to power the device when the RF block is unused. I’d like to optimize the board and avoid populating connections/components that won’t be used.

Questions

• Can the RF section be left unpowered entirely, or do certain rails still need to be supplied?

• Do any RF-related pins need specific pull-ups/pull-downs, or can they be left floating?

• Which RF-path components can be omitted without impacting MCU operation?

• Are there any recommended pin straps or layout considerations for this use case?

Thank you!

Product page: https://www.st.com/en/microcontrollers-microprocessors/stm32wle5cc.html

[STTwo-32]

Hello @B5773 

• HSE is implemented in the radio IP

• SMPS/LDO is implemented in the radio IP, it significantly (around 40%) reduces current consumption also in Run mode of the MCU. If SMPS is not needed, SMPS coil can be removed.

• if VDDSPMS is not powered, then only LPR mode is possible.

There was no primary intent to use it like this. There are several configurations possible, not all were validated in such work condition.

 Best Regards.

STTwo-32