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RTC backup problem with SB45 on nucleo board

xisco
Associate III

Hello,

 

I was trying to use RTC battery backup on a nucleo F446RET6.

The problem was that the battery (CR2032) connected to VBAT tries (and can't) to power all the board.

Looking to schematic diagram, I see that VBAT pin is connected to VDD thru SB45.

Removing SB45 seems that all is working fine.

Is there a reason for SB45 is there?SB45.png

Thanks

1 ACCEPTED SOLUTION

Accepted Solutions

While there is no battery (or any other separate power supply) connected to VBAT, it is recommended to have VBAT connected to VDD.

waclawekjan_0-1731266883772.png

 

JW

View solution in original post

1 REPLY 1

While there is no battery (or any other separate power supply) connected to VBAT, it is recommended to have VBAT connected to VDD.

waclawekjan_0-1731266883772.png

 

JW