STM32H533 ADC VDDA, VREF+ and input voltage range

[thansen]

I'm a little confused about the descriptions of the ADC VDDA, VREF+ and input voltage range.

Do I understand it correctly that

VDD is the device supply

VDDA is the ADC supply

VREF+ is the ADC reference

It says VREF+ can be supplied internally as 1.8 V, 2.048 V or 2.5 V. Range for external Vref+ 1.8V - VDDA.

If I want to use an internal reference and I connect VDDA to VDD to save components what is then my input voltage range?

Is the input voltage range VSS - VDDA, VSS - VREF+ or VSS - VDD?

[AScha.3 · Accepted solution]

So at first : which H533 ? because with small case,  vref = vdda :

see ds:

+

vdda usually = vdd , connected. (on low pin count case also vref+ fixed to vdda, no other/internal vref possible here.)

ADC supply then vss ... vdda (= vdd); input range always vss...vref+;

so if you can select internal vref-> vrefbuf->adc vref+ , input range vss...vref .

[thansen]

Thanks for the clear answer.