STM32WL55CCU6 - QFN missing VR_PA

MWoło.2 · ‎2021-11-21

Hello,

I build my own end node based on STM32WL55CCU6 in the QFN package.

During bring up I noticed missing VR_PA

VDDPA is available on pin 25.

Can someone help me to understand why is missing? I check also on the oscilloscope and is missing too. Nothing happens on this 24 pin (VR_PA). I check soldering and everything looks perfectly not shortcuts or miss connections.

Thanks for any help to resolve this problem.

BR

Michal

Peter BENSCH · ‎2021-11-22

If you want to work with High Output Power PA: have you connected VDDPA to VDD (VDDSMPS)?

Regards

/Peter

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MWoło.2 · ‎2021-11-22

Yes, I made a connection exactly like on the original baseboard Nucleo. My question is do this voltage should be available always or just while sending the data. For LPO, it is 1.35, and for HPO, 3.1V.

Regards

Michal