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

KHarb.1
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:

https://community.st.com/t5/stm32-mcus-products/triangle-wave-dac-output-on-stm32g473-seems-to-be-stuck-enabled/m-p/659118#M240313

2 REPLIES 2

> Is this documented anywhere?

Sure.

waclawekjan_0-1712866314245.png

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

JW

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.

STTwo-32
ST Employee

Hello @KHarb.1 

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

Screenshot_2024-04-11-21-16-08-40_e2d5b3f32b79de1d45acd1fad96fbb0f.jpg

Best Regards.

STTwo-32 

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