is it possible apply higher power in VDDRF? For example I can apply 4.2 V.

[KKIM.6]

I'm designing power supply part of STM32WB55 microcontroller.

I'll use a Li-ion battery for power supply of STM32WB55 microcontroller.

As we know, the microcontroller requires 3.3 V maximum but Li-ion battery can generate maximum 4.2 V.

So, I'll use internal LDO in microcontroller to supply proper voltage from 4.2 V.

However, here is a problem in RF power supply, VDDRF.

I think VDDRF requires 3.3 V but currently I have only one option (4.2 V).

My question is that is it possble use 4.2 V for VDDRF?

or if I apply 4.2 V to LDO, LDO can generate 3.3 V in VDD?

or LDO can supply power to VDDRF internally?

[Andrew Neil · Accepted solution]

Again, what does the datasheet say?

That will list both Absolute Maximum and Operating Maximum values ...

"I think VDDRF requires 3.3 V"

No need to just "think" - the datasheet will tell you for sure.

You really do need to take time to study the datasheet.