Vbat voltage supply to STM32U5G9NJ-DK1

[Sudarshan]

Hello,

We have procured STM32U5G9J-DK1 recently. We have to supply a voltage of 3.6V to its Vbat pin. Datasheet of the Microcontroller (STM32U5G9NJ) say that we can supply a Vbat voltage of 1.6V to 3.6V but schematic of this Discovery kit mentions that "The design supports a VDD_MCU at 1.8V only" (Ref MB1829 schematic of this Discovery kit). Also, whenever I configure any GPIO as output on this kit and Pull it high, it shows 1.8V only. So, my doubt is whether or not we can give 3.6V to Vbat pin. Should we restrict Vbat to 1.8V only ?

With regard,

Sudarshan Chaudhary

[QSHAO.1 · Accepted solution]

The VBAT can be setup to either 1V8 or 3.6V depends on your application. What implemented on STM32U5G9J-DK1 is an example of use case of same VBAT and VDD, however you are allowed to implement a VBAT with voltage in the range of VBAT = 1.65 V to 3.6 V. Thanks!