STSPIN3201 ADC Vref_int channel value has too ripple.

[Ticcola Nessla]

I use STEVAL-STSPIN3201. I was testing ADC channels. I tried to read Vrefint channel. However the value had too ripple(1520-1570). I used F0 discovery board to check Vrefint. There has no ripple. What is the problem on STEVAL-STSTSPIN3201?

[Cristiana SCARAMEL]

Hello @Ticcola Nessla​,

the ADC full scale is VDDA that is generated by internal DC/DC buck regulator.

So you are reading the buck regulator ripple.

In fact, you can use the VREFINT measure to compensate for all other ADC conversions.

This compensation method is described in the STM32F0 family reference manual (RM0091 at page 260).