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Is VREF+ pin required to be connected if VREFBUF is configured as an internal reference on STM32G4?

Associate III

I began using an STM32G473 and the DAC outputs are acting funny. I have VREFBUF configured as an internal reference. Since I'm not using VREF+ as an output, I left the pin unconnected. I posted a thread about it and it was recommended that I connect VREF+ through a cap to ground.  I'm working with a custom board where this isn't possible so I can't test.

I haven't found anything in the documentation that would suggest leaving the VREF+ pin unconnected would have ill effects on DAC outputs. Is this documented anywhere?


Original thread:


> Is this documented anywhere?



Importance of stable VREF+ for stable DAC is not a question, I suppose.


PS. Please don't start new threads while discussing the same issue. Please select @AScha.3 's correct answer as  "Accept as solution" so that the thread is marked as solved.

ST Employee

Hello @KHarb.1 

I suggest you to take a look at the reference design based on the STM32G4 Series on the  AN5093


Best Regards.


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