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Question about multi-layer PCB grounding

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chihhao

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PCB grounding

I have a question for multi-layer PCB grounding.
To use through hole via to connect each ground layer is better or
to use blind via & buried via to connect each ground layer is better ?
Thanks.
 

Re: PCB grounding

Like usually it depends.
In general there is no need to connect every ground plane by via, but blind via & buried via are more expensive than through via. If you dont have to (becouse of eny reason) use blind via don't use it.
In other hand connecting digital GND and RF GND can couse a lot of problems. Also connecting GND of RF PAam with GND of LNamp can couse problems with crosstalks, or even instability of one of them.
So GND in RF design is very important thing, and you have to think every time, when you place via.
Good solution is to connect all ground planes (from different circuits) in only one point. Of course if it is possible.
 

Re: PCB grounding

Connect all GND plane in only one point?
It seems not like the design guideline said.
 

Re: PCB grounding

What I'm going to tell you is that you have to think how and when you can connect ground planes. This is not only choice between through and blind via.
 

Re: PCB grounding

In Theory You Should Have Only One Point Because Of Ground Loops Hazards.
However If You Spread Connection Points Close Then This Can Be Avoid, And Resistance Between Planes Is Lowered.
Other Aproaches Are The 0 OHM RESISTOR Connection (Connection Between Planes Is Done B Resistor), And Make Scratching Between Planes, So Connection Can Be Made Near The System Ground Terminals (Same Plane Is Used, But He Is Scratched Between DIGITAL, And Analogue).
 

Re: PCB grounding

Hi,
if you have 2 or moore gnd planes, but they are the same gnd, no problem to connect the planes with vias trough hole. Not convenient use blind via.

The problem was different you have 2 gnd planes but different gnd, for example digital gnd, and analog. If possible keep this planes Not overlapped and connect te planes in only one point, Bouli and shawndaking are right.

If the circuit are high speed, the situation are moore complex, but is possible to connect the planes (only if are same gnd), with a vias matrix.

In the RF circuit, are not so simple, do you need to control impedance, is not possbile to connect planes with a rule of thumb.

Skywalker.
 

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