Dave,
I use split planes fairly often. The placement of the parts on top and bottom
become the critical point. You don't want to cause or create a loop in the
signal return paths. This may generate "ringing" in critical signals, and
increase magnetic cross talk  between circuits.
I would suggest taking a class or seminar on using split planes and EMC.
Sometimes they are a necessary evil.

There is one scheduled for Boston October 15-16 and Milwaukee September
17-18. Both are presented by The University of Wisconsin.

Hope this helps,
John Shaub
Sr. Designer
Honeywell Inc.

 ----------
From:  [log in to unmask]
Sent:  Tuesday, July 21, 1998 1:37 PM
To:  [log in to unmask]
Cc:  Shaub, John  (PA62)
Subject:  [DC] !!! SPLIT GROUND PLANES !!!

I'm looking for information regarding SPLIT GROUND PLANES.

Experts on grounding, EMI, EMC are teaching that gaps in ground planes
create serious problems.  Component manufacturers, however, continue to
recommend placing gaps under components (such as A/D's and D/A's).

Can anyone:

 - point me in the direction of theoretical reference material
 - relate their experiences / practices

Thanks,
 --
Dave Schaefer                                                      Phone
: (204)631-2298
Senior PWB Designer                                         FAX :
(204)631-2475
NORTEL - Broadband Wireless Access          email : [log in to unmask]
37 Stevenson Road
Winnipeg, MB R3H 0H9

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