STM32U073RBT6 using DAC with Internal Vref (2048mV)

[pyoruya]

I am using the STM32U073RBT6. I want to output DAC using the internal reference (2048mV), but the output is based on VDD_A. Can you provide a specific example of how to use it?

Summary: How to output DAC using the internal reference (2048mV) to PA4 and opamp p_in.

[TDK]

> STM32U073RBT6

This chip does not have a separate VREF+ pin. Its VREF+ pin is tied internally to VDDA. Because of this, you cannot use VREFBUF on this chip.

[pyoruya]

Thank you for your response. I was confused about using the DAC due to the following:

 I expected that in HOLD mode, it would be possible to use the internal REF_V in the DAC.

Could you please clarify once again? Is it not possible to use the internal REF_V (2048mV) as the reference voltage for the DAC or ADC on the STM32U073RBT6?

[pyoruya]

..

[TDK · Accepted solution]

Your chip doesn't have a dedicated VREF+ pin and so you cannot use the VREFBUF at all.

Hold mode is for low power applications where you want to disable the buffer but keep the voltage. It's not relevant here.

https://www.st.com/resource/en/application_note/an5690-vrefbuf-peripheral-applications-and-trimming-technique-stmicroelectronics.pdf