Hello John, the Signal Integrity List may be useful: http://www.freelists.org/cgi-bin/webpage?webpage_id=si-list Subscription http://groups.yahoo.com/group/si-list/messages Archives Regards, Thomas -----Original Message----- From: John Parsons [mailto:[log in to unmask]] Sent: Tuesday, July 08, 2003 10:37 PM Subject: FAB: Impedance Calculations Greetings all, I could use a little help here. I don't have an impedance solver at hand and I have a customer looking for a suggested build for a 10 and 12 layer board with signal traces running at 100ohm (single ended and differential). They will have signal traces at 4-6mil's (I am using 5mil for my rough calculations) but I can't see how to do this with regular FR-4 laminate (Er 4.2). Has anyone build/designed boards with this requirement? Can you give me some clues as to lay-up or laminate spec's that could save me some leg work? Stack is as follows; 1/2oz base copper all layers 10 layer, Sig,Plane,Sig,Plane,Sig,Sig,Plane,Sig,Plane,Sig 12 layer, Sig,Plane,Sig,Sig,Plane,Sig,Sig,Plane,Sig,Sig,Plane,Sig Regards John Parsons --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------