Dave,
Split ground planes are OK as long as you do not route your conductors
across the split.  If you do route across a split, the return current will
have to make a detour at the split, find where the grounds are connected
and then try to meet up with the conductor again.  This will create large
loops. (BAD).  Try to place components so that the conductors that must
cross from one plane to another do so in the same area.  That way you can
join the planes just where the conductors cross over.

John Howard does a course on EMC.  He will be in Milwaukee, WI.  Sept.
17-18  and in Andover (BOSTON) MA  Oct. 15-16.  Call 414-227-3139
University of Wisconsin Milwaukee for more info.

John Laur
Rockwell Automation
Allen-Bradley




Dave Schaefer <[log in to unmask]> on 21/07/98 10:28:28

Please respond to [log in to unmask]

To:   [log in to unmask]
cc:    (bcc: John C Laur/Milwaukee/RA/Rockwell)
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
################################################################
DesignerCouncil E-Mail Forum provided as a free service by IPC using
LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following
text in the body:
To subscribe:   SUBSCRIBE DesignerCouncil <your full name>
To unsubscribe:   SIGNOFF DesignerCouncil
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section
for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or
847-509-9700 ext.312
################################################################

################################################################
DesignerCouncil E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE DesignerCouncil <your full name>
To unsubscribe:   SIGNOFF DesignerCouncil 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################