VREFBUF is inaccurate, causing ADC and DAC peripherals to be innacurate

[RHelv.1]

Hello, I have two different projects in parallel right now, both of which use STM32G0B1 MCUs. On both projects, with completely seperate hardware, the VREFpin that connects to the internal VREFBUF peripheral is innacurate. These pins are just brought out to test points, nothing more. While configured for a 2.5V output, they measure about 2.9V and have more noise on them than I would expect for a reference voltage. Register values are as follows:

VREFBUF_CSR: 0xD

VREFBUF_CCR: 0x18

I've done other STM32 projects using VREFBUF without issues. Is there something different regarding the STM32G0B1 parts? Is anything needed in hardware to support VREFBUF? Our VDD is 3.3V.

Thanks,

Rob

[Chris21]

Do you have appropriate capacitance connected to VREF+?

[RHelv.1]

I do not. Is this required? @Community member​ 

[Chris21]

Yes, according to STM32G0-Analog-Voltage-reference-buffer-VREFBUF.pdf STproduct training document.

[Chris21 · Accepted solution]

Datasheet Power Supply schematic shows 100 nF and 1uF connected to VREF+.

[RHelv.1]

Thank you!