Reply to thread

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

I always flooded my layouts with ground, and it's 100% effective until it isn't. :). Adding a ground flood adds a capacitor to ground of a few pF's to every trace on the board.  Most of the time, it doesn't matter, but it should be a deliberate decision, especially if you have high impedance nets that you are using to form filters.


As an example:  you have a 220k feedback resistor bypassed with a 100pF cap, used in a LPF tuned to 7.2kHz.  10pF parasitic capacitance on a long trace over a ground plane could shift the frequency down almost 800Hz!


At a high level, ground should follow signal, and you should consider the layout as a differential input of your source/signal voltage and ground. As I said, in this design, it may not make much difference, but doing it in this way minimizes problems.


Back
Top