rickman <[email protected]> writes:

> BTW, you are aware that the power plane is just as effective as the
> ground plane for determining the impedance.

Yes, but the OP needs to be aware that care can be required when
switching your signal trace from one layer to another. When you switch
to a layer which references the other supply rail, then the return
current has to also switch layers. If the way it has to do that is
via a decoupling cap a long way away then the current loop can be
quite large.

I got Henry Ott's new book just this morning, and he has some
discussion on p630... If you use Amazon's "search in this book"
feature from here:

http://www.amazon.co.uk/Electromagne...dp/0470189304/

and search for "Changing Reference Planes", you can see pp 630-631.

To the OP - ...and then buy it

Cheers,
Martin

--
[email protected]
TRW Conekt - Consultancy in Engineering, Knowledge and Technology
http://www.conekt.net/electronics.html