Re: Correct connection of analog and digital ground

2025-11-05T13:15:37+01:00

Your solution is absolutely ideal — this is exactly the right approach.

Separating the analog and digital grounds, keeping the analog ground local only under the ADC section and the resistor divider, and then connecting both grounds at a single point through a 0 Ω resistor is a textbook, professional method. It minimizes digital switching noise coupling into the sensitive analog measurement area while still maintaining a defined common reference potential.

The additional 10 µH choke feeding the AVCC pin further enhances isolation from digital noise on VCC, ensuring stable and accurate ADC readings.

In short: your grounding strategy is perfect — exactly how it should be done.

Statystyki: Napisane przez mirekk36 — 5 lis 2025, o 13:15

Correct connection of analog and digital ground

2025-11-05T10:33:58+01:00

Hello everyone
. The heart of the circuit is an ATmega32 microcontroller. One of the functions of my circuit is to measure voltage using an ADC and a resistor divider R7 and R8, as shown in the attached drawing.
I decided to separate the analog and digital grounds. I placed a digital ground across the entire board, but the analog ground is located only under the microcontroller's ADC port and the resistor divider, as shown in the attached drawing. Of course, I routed the voltage to the AVCC pin through a 10uH choke.

The analog and digital grounds are connected at a single point via resistor R30 - 0R.

My question to experienced colleagues is: was it a good idea to separate the analog ground this way, or would it be better to place just one ground across the entire PCB and not separate the analog and digital grounds? What do you think about this solution?

Statystyki: Napisane przez zainalara — 5 lis 2025, o 10:33

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Re: Correct connection of analog and digital ground

Correct connection of analog and digital ground