Hi, I have a 6 layers PCB with this stackup : Top - Signal/ fill with GND Prepeg : 4.6 Int1 : ground plane Core : 5.0 Int2 : Signal/ fill with PWR Prepeg : 33.5 Int3 : Signal/ fill with GND Core : 5 Int4 : Split power plane 3.3V/5V Prepeg : 4.6 Bottom : Signal/fill with GND The dimensions for the core and prepeg are in mils and my operating frequency is 100Mhz. So do you think that I have to worry about the frequencies above 500Mhz because of the lack of power plane decoupling in my stackup? thanks. ------------------------------------------------------------------ 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 technical documents are available at: http://www.si-list.org 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