I agree with Joe for example you would not want to contaminate sensitive analog circuitry with digital noise by using a common ground plane. It is important to use partitioning but as Joe also pointed out it can make things much worse if done incorrectly.
Mark Schmidt Regulatory Compliance X-Rite Incorporated _____ From: [email protected] [mailto:[email protected]] On Behalf Of Joe Randolph Sent: Wednesday, January 16, 2008 9:00 AM To: [email protected]; [email protected] Subject: Re: Gnd/Pwr Planes On 1/16/2008, [email protected] wrote: What are some of the causes that create breaks or slots in ground or power planes in multilayer boards? Voltage partitioning comes to mind and closely spaced vias. Others? It is very common to partition the power and ground planes to help control the return currents for various subsystems on a board. The idea is to keep the return currents localized within each subsystem and then carefully manage the return currents between the subsystems using "bridges" between them. This method can be very effective if done correctly, but it can actually make things worse if done incorrectly. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 (USA) [email protected] http://www.randolph-telecom.com <http://www.randolph-telecom.com/> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
