VSSA VDDA and analog / digital ground separation. What's best?

[d4]

Hello,

I have a mixed signal application in development, a home energy monitor, and following on from the recent PCB version's test results on the effects of noise, and after reading this article, I've decided to separate my digital and analog ground, which makes A LOT of sense.

I have the 100-pin package, STM32F303VE, it has VSSA and VDDA pins. Shall I connect VSSA to analog ground, while connecting VSS (digital) to the digital ground?

I ask because the Analog Dialogue article states that the digital ground of an MCU must be connected to analog ground, for the sampling architecture to have the same reference as the analog elements of the circuit.

However I have reason to believe the sampling architecture of the stm32f3 is connected to VSSA, and therefore can be separated.

I could route all VSS pins to 2-way solder jumpers and could report back with a noise test results on connecting all VSS to either DGND or AGND. If someone already has experience here, I would appreciate the time.

Cheers,

Dan

[d4]

That terminology is useful, cheers.

I have an externally applied voltage dropped across a burden which needs sensing, thus, an absolute measurement is the requirement.

This relates to the need to pay added attention to power supplies and ground loops.

I'll break out VDDA and VSSA to 2-way solder bridges for the next revision... testing etc....