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Message: <blockquote data-quote="Matador" data-source="post: 1021299" data-attributes="member: 44464">I always flooded my layouts with ground, and it's 100% effective until it isn't. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile    :)" loading="lazy" data-shortname=":)" />. 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.</blockquote>