I have to agree with Bharath here: it is almost always safe to split power, and almost alway a bad plan to split ground. We do about 150 designs a year, and perhaps 5 or 10 benefit from split ground planes. A recent consumer product which had been designed with many split ground planes to "help with noise" failed ESD miserably. A re-spin with continuous ground plane passed easily. The same is true for emissions.
Joe is correct in saying that there are some cases where a split ground plane helps, but they are far and away in the minority. Curt in real life Curt McNamara, P.E. // principal electrical engineer Logic Product Development 411 Washington Ave. N. Suite 400 Minneapolis, MN 55401 T // 612.436.5178 F // 612.672.9489 www.logicpd.com / / / / / / / / / / / / / / / / / / / / / / / / / This message (including any attachments) contains confidential information intended for a specific individual and purpose, and is protected by law. If you are not the intended recipient, you should delete this message and are hereby notified that any disclosure, copying, or distribution of this message, or the taking of any action based on it, is strictly prohibited. On Jan 16, 2008, at 11:28 PM, Joe Randolph wrote: On 1/16/2008, Bharathkumar Raju wrote: I hope Randolph means this way : 'Dividing the power plane is good and will improve the situation but dividing the ground plane will only have negative effect.' Hi Bharath: That is not what I meant. In mixed-signal systems that contain analog, digital, and DC/DC converter subsystems, dividing the ground plane can have very beneficial effects if it is done carefully. The goal is to control the flow of ground return currents among the various subsystems. My point was that if it is not done carefully, it can make things worse than if the ground plane had been left continuous. 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
