hello, Stackup : 1 - gnd 2 - digital sig 3 - digital sig 4 - gnd 5 - analog sig 6 - analog sig 7 - gnd 8,9,10,11 ..... notice that the digital signals from layer 3 and the analog signals from layer 5 will probably have return currents on layer 4. question : will the digital return currents cause noise in the analog section, since they both share layer 4 for return currents? (My first guess is yes, but someone mentioned that the skin depth for the return currents is small so they can share layer 4 without effecting each other.) thanks for your input. Jim ------------------------------------------------------------------ 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 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