Hello @all, I done a Mainboard Schematic with gEDA, now I have to layout the hole thing, because I need LVDS,GigE,... I need to care about trace impedance. Because of this, I used wcalc to calculate trace impedance, but now I have some (general) questions about impedance calculations.
For GigE e.g. I need 55Ohm Single- and 100Ohm Diff. Impedance. I used wcalc "Microstrip Analysis" and PCB Values to get the Single-Imp (55Ohm). (w=0,55mm;l=20mm;h=0,38;Er=4,6;Tand=0,015;Tmet=35um,Rho=1,72e-8;100MHz) But now I want to get the diff. Impendance with "Coupled Microstrip Analysis", the only Variables I can influence are w,s,l. If I using w=0,55Ohm (from Single Imp.) it's impossible to get 100Ohm diff. Imp.. Minimal Spacing and Trace width is 0.15mm, if I'm using this, I get nearly 100Ohm diff., but then my single Imp. is also 100Ohm. So, please - just give me a hint. Do I completly misunderstood wcalc!? I really need to get this pcb to fab... - Any tips would be greatly appreciated. Greetings, _______________________________________________________________________________________________________________________ cand. Dipl.-Ing. (FH) Marcel Schmedes Research & Technology Cockpit Cabin Control Diehl Aerospace GmbH An der Sandelmuehle 13 D-60439 Frankfurt/Main Phone: +49 (0) 69 5805-1712 Mail: marcel.schmedes.ext...@diehl-aerospace.de www. http://www.diehl-aerospace.de . Der Inhalt dieser E-Mail ist für den Absender rechtlich nicht verbindlich. Informieren Sie uns bitte, wenn Sie diese E-Mail fälschlicherweise erhalten haben (Fax: +49-7551-891-4001). Bitte löschen Sie in diesem Fall die Nachricht. Jede Form der weiteren Benutzung ist untersagt. . The content of this e-mail is not legally binding upon the sender. If this e-mail was transmitted to you by error, then please inform us accordingly (Fax: +49-7551-891-4001). In such case you are requested to erase the message. Any use of such e-mail message is strictly prohibited. _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user