Stability of the VDDA when using a VREF

[DDDRRRR]

Good day, I am interested in the following question: in the F7 series microcontrollers there is a Vref pin. If I use an external reference voltage source, do I need to stabilize VDDA or in this case the stability of the analog power supply does not affect the accuracy of the results of the operation of the analog modules of the microcontroller (ADC and DAC)?

[MasterT]

The parameter name is PSRR, I don't see it specified for ADC in F767 datasheet. But there is PSRR for DAC.

Typical -67 , max -40 dB. Means analog voltage domain gets into dac output as 1 : 100, 100 mV ripple 'd produce 1mV noise. I'd expect about same value for ADC.  Reference voltage gets into as 1 : 1.

[DDDRRRR]

Thanks for the reply, but I don't quite understand the conclusion of your post. The 1:1 ratio looks much worse than 1:100

[MasterT]

Right, means filtering Reference voltage is at highest priority. Analog power voltage filtering has no practical meaning for 12-bits adc, 16-bits and above  

[DDDRRRR]

I don't quite understand the logic.

The 100mV pulsation is quite large.
Let's say we take the Ref3033 with a stability of 0.2%. At the output of 3300mV, this is about 6.6mV of noise pulsation.

If we have 1:1 coefficient for Vref, we get 6.6mV pulsation, which much worse than 1:100 for VDDA.

What is the point of installing Vref then?