Scott, You may also like to look at the application notes on the Polar site: www.polarinstruments.com/support/cits/cits_index.html Kind regards Martyn Gaudion Polar Instruments T: + 44 1481 253081 F: + 44 1481 252476 M: +44 7710 522748 E: [log in to unmask] www.polarinstruments.com At 09:52 30/11/01 -0500, you wrote: > >From: <mailto:[log in to unmask]>Scott Westheimer >To: <mailto:[log in to unmask]>Technet >Sent: Friday, November 30, 2001 9:06 AM >Subject: Differential impedance > >I have a question regarding differential signal pairs and differential >impedance that I hope someone can help me with. We are designing a 14 >layer board and the finished thickness needs to .062" and we require 100 >ohms. Some of the internal layers we have split planes. Would these be >considered strip line or microstrips? > >Thanks > >Scott