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I’ve recently been reviewing some PCB designs to learn good practices.

One thing I’ve seen is that a ground plane is used on top layer between the components and traces.

Is this a good practice and why is it a good practice, what does it help

citizen
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Reece Smith
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1 Answers1

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That's not a ground plane as much as it is just a copper pour to fill up space between traces that has been grounded so it doesn't float and cause noise problems. It means etching is faster and produces less waste while maintaining copper balance with other layers which, in the past, was important to prevent warping.

For a true ground plane to do its job it needs to run under the traces so the returning ground currents for that trace run underneath the trace on the plane which minimizes loop area and thus inductance.

DKNguyen
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  • Not quite exact, even on the side ground tracks offer some electrostatic shielding; they are called guard loops but the effect applies in general. And of course in controlled impedance they make the difference between a microstrip and a coplanar wave guide. – Lorenzo Marcantonio Aug 06 '21 at 07:39