If I supply power only for SMPS, the microcontroller looks not booting. is it correct?

[KKIM.6]

I'm designing a power line for the STM32WB55 microcontroller.

I'm checking the power system on the Nucleo-68 board but I found that the microcontroller cannot send a Bluetooth signal if I connect Vsmps only when booting the microcontroller.

I also found that it successfully work after removing VDD_MCU and VRF after finishing booting.

Is it correct?

It would mean I have to supply power to VDD also.

I also found that connecting VRF makes Bluetooth signal better.

[Remy ISSALYS · Accepted solution]

Hello,

Please have a look to chap 3.7 of the datasheet DS11929 for power supply management.

Best Regards