How about this 8-layer stackup? 1) Signals (Single Ended) 2) GND 3) Signals (Differential) 4) +5V 5) +12V 6) Signals (Single Ended) 7) GND 8) Signals (Single Ended) Thanks. Kevin >From: "Moran, Brian P" <brian.p.moran@xxxxxxxxx> >To: <kevin98146@xxxxxxxxxxx>, <si-list@xxxxxxxxxxxxx> >Subject: RE: [SI-LIST] 6-layer vs 7-layer PCB Stackup >Date: Tue, 1 Jun 2004 14:07:28 -0700 > >Kevin, > >Your 7 layer stackup may look symetrical but if you fill in the pre-preg >and core designations >it becomes clear that its not actaully symetrical. Not unless you have >back to back pre-pregs in >the center of the stackup. I'm not a PCB fab guy but it doesn't look >kosher to me. You'd be better >off going with 6 layers, or if neccessary to a truly symetrical 8 layer. >Money spent on backplanes >is usually money well spent. > > >Brian P. Moran >Calistoga SIE Kit Leader >Intel Corporation >brian.p.moran@xxxxxxxxx > > >-----Original Message----- >From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] >On Behalf Of Kevin Khuu >Sent: Tuesday, June 01, 2004 1:42 PM >To: si-list@xxxxxxxxxxxxx >Subject: [SI-LIST] 6-layer vs 7-layer PCB Stackup > >Hi All, > >I'm working on a backplane design and come up with the following 7-layer >PCB >stackup: > >1) Signal (Single Ended Signals) >2) +5V >3) GND >4) Signal (Diffential Signals, high speed) >5) GND >6) +12V >7) Signal (Single Ended Signals and +3.3V trace) > >I don't really need two GND planes, but the reason I added the second >GND >plane (layer 5) was because of symmetry and balancing PCB stackup. How >does >this stackup compare to the 6-layer stackup (without the second GND >layer on >layer 5)? > >Your comments/ideas would be greatly appreciated. > >Thanks, >Kevin > >_________________________________________________________________ >Learn to simplify your finances and your life in Streamline Your Life >from >MSN Money. http://special.msn.com/money/0405streamline.armx > >------------------------------------------------------------------ >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 FAQ wiki page is located at: > http://si-list.org/wiki/wiki.pl?Si-List_FAQ > >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 > > _________________________________________________________________ Express yourself with the new version of MSN Messenger! Download today - it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/ ------------------------------------------------------------------ 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 FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ 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