What's the best of getting signal out of a guard ring on PCB?

[Ghost Tweaker]

Hi everyone,

a small question about guard rings: what is the best way to get the signal out of the guard ring? use a via to change layer and pass under the ring or do you let a small "open section" in the guard ring? also the ring should be connected to the ground with the max number of vias right?

Thanx in advance for your help

 

[biff44]

guard ring pcb

What do you mean by a "guard ring"? The only guard rings I have seen are with high impedance LOW FREQUENCY op amp inputs where you do not want to have any leakage currents.

 

[Ghost Tweaker]

pcb guard

To me this is a track forming a ring around a sensitive section of the circuit like the VCO. It is connected to ground and a metallic box is usually soldered to the track in order to isolate the circuit section from the rest of the PCB (interferers, ...).

Added after 30 minutes:

 

[biff44]

guard ring in pcb layout

You can do a buried trace on a multilayer board, you can do a very short jumper trace on the backside of a 1 layer board, you can use solder mask over the trace and run one over the top layer (you have to bread the ground ring where the trace goes thru, but you use plated holes to the ground layer on either side), if it is a board without solder mask you can have a doghouse door cut into the metal can wall to let the signal thru.