At a high-level, asymmetry causes warped boards. Warped boards causes assembly issues. Aubrey Sparkman Enterprise Engineering Signal Integrity Team Dell, Inc. Aubrey_Sparkman@xxxxxxxx (512) 723-3592 > -----Original Message----- > From: si-list-bounce@xxxxxxxxxxxxx > [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Perry Qu > Sent: Thursday, January 22, 2004 9:40 AM > To: mkhusid@xxxxxxxxxx > Cc: 'Nosovitski, Alexander (Contr) '; 'si-list@xxxxxxxxxxxxx ' > Subject: [SI-LIST] Re: PCB STACKUP > > > Can someone comment on the impact of assymetrical stackup on > PCB yield ? > > Thanks > > Perry > > Michael Khusid wrote: > > > Alexander, > > > > Unless I miscounted, I can see 27 layers in your stackup. > An odd number of > > layers will get you an assymetrical stackup and will cause > PCB warpage. > > > > Michael > > > > -----Original Message----- > > From: Nosovitski, Alexander (Contr) > > To: si-list@xxxxxxxxxxxxx > > Sent: 1/21/04 4:02 PM > > Subject: [SI-LIST] PCB STACKUP > > > > Hello si-list, > > > > The design I am working on has a dense placement. > > > > The proposed stack up looks as follow: > > > > TOP > > POWER_ANALOG > > DIFF_SIGNAL (Gb/s signals) > > AGND > > > > GND > > POWER > > S > > S > > GND > > POWER > > S > > S > > GND > > SPLIT_POWER > > GND > > S > > S > > POWER > > GND > > S > > S > > GND > > > > AGND > > DIFF_SIGNAL_ANALOG (Gb/s signals) > > POWER ANALOG > > > > BOTTOM > > > > All signal layers are 0.5 Oz copper and > > > > All planes are solid ( except one in the middle) with 0.5 > Oz copper. > > > > The diff. signals are running at 2.5Gb/s. > > > > There are different opinions about analog plane location. > > > > Could the arrangement above cause a problem? > > > > What else should I be concern about? > > > > Any help or suggestion is appreciated! > > > > Regards, > > > > Alexander Nosovitski > > > > > > > > > > > > -----Original Message----- > > From: Salkow, Steven [mailto:steven.salkow@xxxxxxxx] > > Sent: Wednesday, January 21, 2004 1:57 PM > > To: weirsp@xxxxxxxxxx; fred@xxxxxxxxxxxxx; kar_thik_v1@xxxxxxxxx > > Cc: si-list@xxxxxxxxxxxxx > > Subject: [SI-LIST] Re: Looking for thin dielectric tape > > > > 4 mil prepreg (pcb laminate) is generally available from > anyone doing > > multilayer PCB. You may also get samples from laminate > vendors (dupont, > > Norplex) (sprayed with Scotch 444 adhesive for cold > adhesion to copper > > foils) > > 3M (tape division) have exactly what your looking for up to 36" wide > > slit to any width but they have minimum qtys > > > > see > > > http://products3.3m.com/catalog/us/en001/utilities_telecom/oem > _electrica > > > l/node_R5MTBSFVGPbe/root_GST1T4S9TCgv/vroot_GSHBRQT7DVge/gvel_ > BBGZX3B1QG > > gl/theme_us_oemeletrical_3_0/command_AbcPageHandler/output_html > > > > Catalog on the above page for download > > > > Steve Salkow > > Lockheed Martin > > 3200 Zanker Road > > San Jose, CA 95134 > > (408) 473-4058 (san Jose) > > (408) 742-4162 (Sunnyvale) > > steven.salkow@xxxxxxxx > > salkow@xxxxxxxxxxxx > > (925) 462-1075 Home > > (925-) 487-5946 Cell > > (408) 468-7271 Numeric Pager > > > > -----Original Message----- > > From: si-list-bounce@xxxxxxxxxxxxx > > [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of steve weir > > Sent: Tuesday, January 20, 2004 11:17 PM > > To: fred@xxxxxxxxxxxxx; kar_thik_v1@xxxxxxxxx > > Cc: si-list@xxxxxxxxxxxxx > > Subject: [SI-LIST] Re: Looking for thin dielectric tape > > > > If you want to lay out a board, onesy, twosy, Express PCB > is not a bad > > way > > to go. www.expresspcb.com It sure beats the Bishop > Graphics adhesive > > backed Cu tape, or a bathroom full of ferric chloride. > > > > Steve. > > At 01:44 PM 1/20/2004 -0800, Fred Townsend wrote: > > >The last time I check you could still get mylar sheeting at most > > >drafting and staionary stores. You would to apply your own > adhesive. > > >Comes in 4 and 7 mil thicknesses. You can also get > polyester sheeting > > >frosted one side and adhesive on the other for making > labels. Failing > > >that how about 3M's double sticky magic tape? > > > > > >Fred Townsend > > > > > >Karthik V wrote: > > > > > > >Hello, > > > > > > > > I am a student at the State University of New York. I am > > > looking for a double sided sticky dielectric tape (more > like a sheet ) > > of > > > thickness about 4mils (0.1mm) and with a dielectric constant of > > > around 4, to use between copper sheets - to make a > "temporary board". > > I > > > tried things like epoxy, but it's almost impossible to > get it so thin > > and > > > still provide infinite DC resistance. > > > > > > > > Could anyone point me to places where I could > look for this > > > > > kind of stuff. Is there anything else I could try to get the > > dielectric > > > (with Dk around 4) so thin ( apart from elaborate processes ) . > > > > > > > >thanks in advance, > > > >Karthik, > > > > > > > >--------------------------------- > > > >Do you Yahoo!? > > > >Yahoo! Hotjobs: Enter the "Signing Bonus" Sweepstakes > > > > > > > > >------------------------------------------------------------------ > > > >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 > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >------------------------------------------------------------------ > > >To unsubscribe from si-list: > > 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> > > > 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 > > > > > > ------------------------------------------------------------------ > > 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 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> //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 > > > > -- > Perry Qu > > Design & Qualification | 600 March Road > Alcatel Canada | Ottawa, ON K2K 2E6, Canada > > DID: (613) 7846720 | FAX: (613) 5993642 > > > ------------------------------------------------------------------ > 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 > > ------------------------------------------------------------------ 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