I would be more concerned with splitting the ground plane than what = layers to use. Splitting a ground plane can cause return current loop = problems. It is best not to cut up the ground planes if all possible. Doug Hopperstad Qlogic 6321 Bury Drive Eden Prairie, MN Phone: (952) 932-4007 Fax: (952) 932-4037 doug.hopperstad@xxxxxxxxxx -----Original Message----- From: Pat Sharkey [mailto:psharkey@xxxxxxxxxxx] Sent: Friday, February 01, 2002 8:10 AM To: Si-List@Freelists. Org Subject: [SI-LIST] Split Plane Routing=20 Hello all, Given the following stackup with planes split in different areas -=20 1 - S1 2 - GND (SPLIT 1) 3 - S2 4 - GND(SPLIT 2) 5 - POWER(SPLIT 3) 6 - S3 7 - GND (SPLIT 4) 8 - S4. For a signal which originates on layer 8, should the signal only be routed on layers 6 & 8? Or, can layers 1 and 3 also be used to cross a plane split on layer 7, assuming layers 2 and 4 are not split in the=20 same place (z axis)? Thanks in advance, Pat ------------------------------------------------------------------ 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: =20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages=20 Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =20 ------------------------------------------------------------------ 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //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