Hi We are in the process of laying out a PCB, due to safety requirements we can not provide a full coverage ground plane in one section of our circuit. In this area high speed signals are required to travel to other components (100 MHz, 1ns edge rates). We do have room to place a restricted ground plane under these traces to help reduce emissions and control impedances. What would be considered the minimum ground plane width to provide sufficient coverage to control impedance and provide a return path? Would 20H be a good start? Erin ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu