At 09:58 AM 10/27/98 -0800, Olson, Jack C wrote:
>
>This may be a niave question,
>but if Kirchoff's law states that for every current there is a return
>current, then it seems that everything that happens on a power plane would
>have a corresponding effect on the ground plane.
>
>So why is a ground plane any better reference plane than a power plane?
>(they are both "power planes" in effect?)
>
>Jack

In short, unintended current flow.

If you lay out the board with power and ground
planes as you intend, these return paths *may*
be unintended causing crosstalk to occur in
apparently isolated circuits.

As much as you want to keep power noise from
getting into your circuits, you should also
be aware of getting your circuit noise into
your power circuits.  It's a two way street.
I'm not sure that this is anything original.
In fact, I'm not sure where I learned this.

And also, this is strictly my own *preference*.

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