Brent, Yes, from what I understand this is correct but that is my problem, I don't have a calculator to model this design to verify the parameters. I could do as Jason has suggested and just build to "spec" but I don't know if a complete material spec has been provided. I am enquiring as to this. I would however still like to understand the design, especially when the designer has come to us to help him understand and verify the design. Thanks to all for the input - keep it coming. John > -----Original Message----- > From: TechNet [mailto:[log in to unmask]]On Behalf Of Alcorn, Brent > Sent: November 20, 2003 8:36 AM > To: [log in to unmask] > Subject: Re: [TN] Co-planar Impedance Calculations > > > Perhaps the "other" trace is the reference? Although ideally,I > believe, you > would want the reference to be about 2x the width of the signal trace. > Perhaps the design dictates that each signal has its own reference?? > > Just my 2cents or 1.4 CDN. > Brent --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------