I think, as always, the answer is: It depends. If you have a run that carries 6 amps on a tiny board and you don't have room to clear around an 0603 capacitor pad and still keep the minimum copper width you need, or by doing so you would sacrifice another aspect of the design, then perhaps it's OK to bury the pad in the 6A trace. If you bury all GND pads in a plane for no particular reason, perhaps you ought to rethink what you're doing. I still think a big part of what we get paid for is to pick the best compromise. Purchasing, Packaging, Engineering, Assembly, and Test: Pick one and imagine doing a board only from that perspective. Would that design please the others? Or, try to imagine a design where all agreed that what you'd done was perfect (if you can imagine that, then you're not imagining the same kind of purchasing people I deal with - because if suppliers were paying us for the privilege of giving us stuff, my folks would say we should be getting paid more). My goal is to not piss anyone off too bad. And if someone is mildly perturbed from time to time but agrees that I did that right thing after I've explained why, I feel pretty good. -Chris (el CID) "Allen T. Maddox" <allen.t.maddox@GAI-TRONIC To: [log in to unmask] S.COM> cc: Sent by: DesignerCouncil Subject: [DC] Trace width ratio to <[log in to unmask]> pad 07/27/2005 02:47 PM Please respond to "(Designers Council Forum)"; Please respond to "Allen T. Maddox" Hey Folks, I was always told to NOT exit a pad, especially a SMT pad, with a trace the same width of the pad for the reason of dissipating the heat off the pad and creating soldering issues. I have an engineer who doesn't believe me and wants proof. Does anyone have any articles that support what I've been taught, or have I been mislead all these years? Thanks, Allen Maddox C.I.D. Sr. PC Board Designer GAI-Tronics, Corp 610-796-5854 PO Box 1060 Reading, PA 19607-1060 [log in to unmask] www.gai-tronics.com ******************************************************************* This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept for the presence of computer viruses. www.hubbell.com - Hubbell Incorporated --------------------------------------------------------------------------------- DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF DesignerCouncil. To temporarily stop/(restart) delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL/(MAIL) Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF DesignerCouncil. To temporarily stop/(restart) delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL/(MAIL) Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ---------------------------------------------------------------------------------