STM32U5A5 Power Sequence

[dvir1092]

Hi All,

There is any problem if VBAT powered before VDD? (VBAT is another supply that feeds from Battery with LDO ) 

I deep dive all the datasheet and didn't find any reminder about it.

[TDK]

No, there is no issue with VBAT present before VDD.

The whole reason for VBAT is to have a battery backup for certain things on the chip like RTC when power is otherwise not available. If VDD was required for VBAT, it would prevent that capability.

[Mageee]

No problem—VBAT can be powered before VDD. It’s designed for battery backup (e.g., RTC) even when VDD is off.