What is the maximum input voltage for the external voltage regulator of the stm32 bluepill?

[HAbay.1]

I am referring to the regulator connected to the usb 5V ( the 5V pin), can it handle a voltage of 12v and step it down to 3.3V for the chip? if not then what is the limit?

[Tesla DeLorean]

Check the schematic and placed components on the board you have

RT9193-33 looks to max out at 5.5V

https://www.richtek.com/assets/product_file/RT9193/DS9193-16.pdf

[Uwe Bonnes]

Bluepill is produced by many asian companies. Parts used may differ, but assuming 5.5 V max is a good guess.