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MWoło.2
Senior III
Nov 21, 2021 1:19 PM UTC
Question

STM32WL55CCU6 - QFN missing VR_PA

Hello,

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

During bring up I noticed missing VR_PA

0693W00000GYKtXQAX.pngVDDPA 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

This topic has been closed for replies.

2 replies

Peter BENSCH
ST Technical Moderator
Nov 22, 2021 10:25 AM UTC

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
MWoło.2Author
Senior III
Nov 22, 2021 7:23 PM UTC

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.

0693W00000GYUVVQA5.png 

Regards

Michal