Differentiating Analog and Digital ground

[alapshah93]

Hello all,

I am new to Altium designer and in my pcb design, there are both analog and digital grounds.

I am not sure about the exact solution and would appreciate if someone can help me with this. I tried to find answer on google but some says that we should partition analog and digital ground planes with star connection while some says that it's not advisable. What will be the best solution to this for 50 MHz circuitry with sensitive components?

Thanks in advance!

 

[KlausST]

Hi,

You first need to decide what section you want to split. (Clean analog, digital, power, maybe smps. ..)
Then think about placement. Maybe you have some placement restrictions. What size do the areas need?
Then you should think about (pulsed) high currents. How to handle it not to interfere other signals
Then about the devices and the signal paths that "connect" different sections. Like ADC, it needs signals to the digital section, needs clean analog gnd and supplies, but maybe needs a clean path to the power section...

I often use only one gnd plane and place splits. Usually a 270° or more split around a switch mode supply circuit.
Another member had a good picture. Imagine the Gnd plane as the surface of a lake. Throw a stone into the lake and see how the waves behave. Build imaginary walls (splits) to keep the waves in a restricted area.

Klaus