As with everything, there are pros/cons to each. In his e-mail, Mark referred to a "special order 3113". That implies some challenges, perhaps including delivery delays, a limited supply base, and/or significant cost adder. Rotating the image would eliminate that problem, albeit with its own complications. Just suggesting an alternative; I don't know which is the most attractive for this particular application. Jeff Loyer -----Original Message----- From: Lee Ritchey [mailto:leeritchey@xxxxxxxxxxxxx]=20 Sent: Monday, December 03, 2007 9:23 AM To: Loyer, Jeff; mark.hinton@xxxxxxxxxxxxx Cc: si-list Subject: RE: [SI-LIST] Re: fiber-weave effect alive and well? Why do that and make either CAD or Fab tougher when usinghte right glass weave solved the problem nicely? Lee Ritchey > [Original Message] > From: Loyer, Jeff <jeff.loyer@xxxxxxxxx> > To: <mark.hinton@xxxxxxxxxxxxx> > Cc: si-list <si-list@xxxxxxxxxxxxx> > Date: 12/3/2007 9:02:02 AM > Subject: [SI-LIST] Re: fiber-weave effect alive and well? > > Mark, > For a low-volume test PCB, why don't you tweak the artwork 10 degrees? > > Jeff Loyer > > -----Original Message----- > From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] > On Behalf Of HINTON,MARK > Sent: Friday, November 30, 2007 2:48 PM > To: leeritchey@xxxxxxxxxxxxx > Cc: si-list > Subject: [SI-LIST] Re: fiber-weave effect alive and well? > > Lee, > > Have you tested 2116 glass yet? I'm doing a low-volume test PCB, and I > may have to choose between 2116 or a high-cost special order of 3113. > If you haven't tested it yet, would you venture an educated guess on how > it would perform? I've got pretty wide traces (9.5 mils). > > Thank you, > Mark > > > > -----Original Message----- > From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] > On Behalf Of Lee Ritchey > Sent: Saturday, September 15, 2007 11:23 AM > To: Scott McMorrow; Perry.Qu@xxxxxxxxxxxxxxxxxx > Cc: si-list > Subject: [SI-LIST] Re: fiber-weave effect alive and well? > > The weave I document is 3313 glass. It is widely used in Asia and is a > stock weave from Isola. We just completed testing on 2113 weave and > obtained similar results. The two thin weaves that are at the root of > the > problem are 106 and 1080. 3313 has not been widely used by US > fabricators, > I suspect because designers have been asking for the thinnest possible > laminates and that is why 1080 and 106 are used most often in the US. > You > don't get 3313 and 2113 here unless you stick to your guns and insist on > it. When you do, there are no real problems. > > We've just completed testing two designs with 48 ports of 10 GE with > superb > results. One used 2113 and the other 3313. > > 7628 is about as coarse as the cloth used to make levis. Not a good > choice. > > Lee > > > > [Original Message] > > From: Scott McMorrow <scott@xxxxxxxxxxxxx> > > To: <Perry.Qu@xxxxxxxxxxxxxxxxxx> > > Cc: si-list <si-list@xxxxxxxxxxxxx> > > Date: 9/14/2007 1:21:15 PM > > Subject: [SI-LIST] Re: fiber-weave effect alive and well? > > > > Perry > > Fiber-weave effects are alive and well, and IMO should be considered > by=3D3D20 > > every designer concerned with 6 Gbps or higher differential serial > data=3D3D20 > > communications channels on PCBs, backplanes, and single-ended =3D > skew=3D3D20 > > controlled parallel buses. Jeff's paper is real life, building > upon=3D3D20 > > about 5 years of good research at Intel. The method that is used > is=3D3D20 > > quite valid and will be seen in real designs. The Intel research > is=3D3D20 > > able to better characterize weave skew using physical nyquist sampling > > > techniques. Yes, with different trace jogs you will see all sorts > of=3D3D20 > > potential alignments, but in the worst case you will still find > that=3D3D20 > > traces can have significant lengths of worst case fiber weave=3D3D20 > > alignment. If you are trying to design systems with 1000's = of=3D3D20 > > differential pairs, there is a statistical certainty that one or more > of=3D3D20 > > those pairs will have skew close to the absolute worst case, if =3D > not=3D3D20 > > designed to compensate for laminate weave anisotropy. > > > > The problem is most pronounced with weaves that have large holes > without=3D3D20 > > fiber in the weave pattern, but you will also see issues with =3D > core=3D3D20 > > materials that are often constructed with large diameter fibers, > like=3D3D20 > > 7628 material. The fiberglass the Lee proposes to use does have > some=3D3D20 > > benefits, however, it does not totally eliminate the fiber weave=3D3D20 > > problem. It reduces it to a lower level. Unfortunately, it is not > a=3D3D20 > > widely manufactured laminate weave. > > > > There are patented techniques for improving weave-induced skew, > which=3D3D20 > > must be licensed. There are also some non-patented techniques, > which=3D3D20 > > may also be used that are not quite as effective as the patented=3D3D20 > > techniques, but nevertheless can be used to design robust systems. = =3D > =3D3D20 > > There is also some silicon IP that can be used to = automatically=3D3D20 > > compensate for skew, and is finding it's way into test > instrumentation. > > > > > > regards, > > > > Scott > > > > Scott McMorrow > > Teraspeed Consulting Group LLC > > 121 North River Drive > > Narragansett, RI 02882 > > (401) 284-1827 Business > > (401) 284-1840 Fax > > > > http://www.teraspeed.com > > > > Teraspeed(r) is the registered service mark of > > Teraspeed Consulting Group LLC > > > > > > > > QU Perry wrote: > > > I would be interested to see a link as well. > > > > > > Jeff's paper on DesignCon2007 is convincing to me that this is > something > > > we need to pay attention. Real life design will probably not be as > bad > > > as the theoretical estimate since most of the diff pair routing we > have > > > on the PCB is not likely to run a long length non-stop in parallel > with > > > edge. The "jog" as is called in the paper is very common due to vias > etc > > > and pretty random. > > > > > > Also from the data we got from PCB vendor, it appears that thinner > > > dielectric substrate the worse fibre weave effect as the gap between > the > > > fiber is larger. Has this been looked at ? > > > > > > Regards > > > > > > Perry > > > > > > > =3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D= 3D3D3D=3D3D3D3D=3D3 D=3D > 3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3 > D=3D3D > = 3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3= D=3D3D3D3D > =3D3D3D3D=3D3D3D > > > =3D3D > =3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D= 3D3D3D=3D3D3D3D=3D3 D=3D > 3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3 > D=3D3D > 20 > > > > > > Perry Qu=3D3D3D20 > > > > > > Design & Qualification, Alcatel-Lucent Canada Inc. > > > > > > 600 March Road, Ottawa ON, K2K 2E6, Canada=3D3D3D20 > > > > > > DID: 613-7846720 Fax: 613-5993642=3D3D3D20 > > > > > > Email: perry.qu@xxxxxxxxxxxxxxxxxx=3D3D3D20 > > > > > > > =3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D= 3D3D3D=3D3D3D3D=3D3 D=3D > 3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3 > D=3D3D > = 3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3= D=3D3D3D3D > =3D3D3D3D=3D3D3D > > > =3D3D > =3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D= 3D3D3D=3D3D3D3D=3D3 D=3D > 3D3D=3D3D3D3D=3D3D3D3D=3D3D3D3D=3D3D3 > D=3D3D > 20 > > > > > > =3D3D3D20 > > > > > > =3D3D20 > > >> -----Original Message----- > > >> From: si-list-bounce@xxxxxxxxxxxxx=3D3D3D20 > > >> [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of=3D3D3D20 > > >> Aubrey_Sparkman@xxxxxxxx > > >> Sent: Friday, September 14, 2007 1:59 PM > > >> To: leeritchey@xxxxxxxxxxxxx; rdudek@xxxxxxxxxxxxxxx;=3D3D3D20 > > >> si-list@xxxxxxxxxxxxx > > >> Subject: [SI-LIST] Re: fiber-weave effect alive and well? > > >> =3D3D3D20 > > >> Would you like to share a link?=3D3D3D3D20 > > >> =3D3D3D20 > > >> =3D3D3D20 > > >> Aubrey Sparkman=3D3D3D3D20 > > >> Enterprise Engineering Signal Integrity Team=3D3D3D3D20 Dell, > Inc.=3D3D3D3D20=3D3D3D20 > > >> Aubrey_Sparkman@xxxxxxxx=3D3D3D3D20 > > >> (512) 723-3592=3D3D3D3D20 > > >> "Discovery consists of seeing what everybody has seen = and=3D3D3D20 > > >> thinking what nobody else has thought." - Jonathan Swift > > >> =3D3D3D20 > > >> =3D3D3D20 > > >> -----Original Message----- > > >> From: si-list-bounce@xxxxxxxxxxxxx=3D3D3D20 > > >> [mailto:si-list-bounce@xxxxxxxxxxxxx] > > >> On Behalf Of Lee Ritchey > > >> Sent: Friday, September 14, 2007 11:36 AM > > >> To: Russell S. Dudek Jr.; si-list@xxxxxxxxxxxxx > > >> Subject: [SI-LIST] Re: fiber-weave effect alive and well? > > >> =3D3D3D20 > > >> We already have a glass weave solution. Check my column in=3D3D3D20 > > >> the April issue of Circuitree magazine. > > >> =3D3D3D20 > > >> Lee Ritchey > > >> =3D3D3D20 > > >> =3D3D3D20 > > >> =3D3D20 > > >>> [Original Message] > > >>> From: Russell S. Dudek Jr. <rdudek@xxxxxxxxxxxxxxx> > > >>> To: <si-list@xxxxxxxxxxxxx> > > >>> Date: 9/12/2007 1:10:28 PM > > >>> Subject: [SI-LIST] Re: fiber-weave effect alive and well? > > >>> > > >>> Steve, > > >>> =3D3D3D3D20 > > >>> I agree, Fiber Weave Effect (FEW) has most certainly = been=3D3D3D20 > > >>> =3D3D20 > > >> confirmed by > > >> such > > >> =3D3D20 > > >>> research. However, there is a new change in the wind. = I=3D3D3D20 > > >>> =3D3D20 > > >> have the=3D3D3D3D20=3D3D3D20 > > >> =3D3D20 > > >>> unique opportunity, as a technical liaison, to enable a=3D3D3D20 > > >>> =3D3D20 > > >> technology=3D3D3D3D20=3D3D3D20 > > >> =3D3D20 > > >>> that may put > > >>> =3D3D20 > > >> an > > >> =3D3D20 > > >>> end to FWE as a consideration in high-speed designs. = We=3D3D3D20 > > >>> =3D3D20 > > >> all know that > > >> =3D3D3D20 > > >> =3D3D20 > > >>> the crux of the matter is the glass weave and its effect on=3D3D3D20 > > >>> =3D3D20 > > >> localized > > >> Er. > > >> =3D3D20 > > >>> Either get ride of the reinforcement layer completely or > more=3D3D3D3D20=3D3D3D20 > > >>> challenging change the fundamentals of the glass weave fabrication > > >>> =3D3D20 > > >> process (GWFP). > > >> =3D3D20 > > >>> =3D3D3D3D20 > > >>> We have taken the more challenging (and fun) approach and =3D3D > have=3D3D3D20 > > >>> rocked=3D3D3D3D20 the fundamentals the GWFP. I cannot disclose much > the=3D3D3D20 > > >>> specifics of=3D3D3D3D20 the technology and our partners in such =3D3D > an=3D3D3D20 > > >>> =3D3D20 > > >> open forum. =3D3D3D20 > > >> =3D3D20 > > >>> However, if=3D3D3D3D20 you are interested learning more feel =3D > free=3D3D3D20 > > >>> =3D3D20 > > >> to contact=3D3D3D20 > > >> =3D3D20 > > >>> me and we can=3D3D3D3D20 get the proper NDAs in place to =3D3D > facilitate=3D3D3D20 > > >>> =3D3D20 > > >> such a discussion. > > >> =3D3D20 > > >>> =3D3D3D3D20 > > >>> RD > > >>> =3D3D3D3D20 > > >>> Russell Dudek > > >>> Technology Specialist > > >>> Compunetics, Inc. > > >>> 700 Seco Road > > >>> Monroeville, PA 15146 > > >>> 412-858-6264 > > >>> rdudek@xxxxxxxxxxxxxxx > > >>> www.compunetics.com <http://www.compunetics.com/> =3D3D3D3D20 > > >>> > > >>> To see where no one notices the contrast of white on white is = =3D > =3D3D3D > > >>> =3D3D20 > > > an=3D3D3D3D20=3D3D3D20 > > > =3D3D20 > > >>> indispensable virtue of infinite potential. > > >>> > > >>> =3D3D3D3D20 > > >>> > > >>> > > >>> > > >>> ------------------------------------------------------------------ > > >>> To unsubscribe from si-list: > > >>> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the=3D3D3D20 > > >>> =3D3D20 > > >> Subject field > > >> =3D3D20 > > >>> 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.net > > >>> > > >>> List archives are viewable at: =3D3D3D3D20 > > >>> //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 > > >>> =3D3D3D3D20 > > >>> =3D3D20 > > >> =3D3D3D20 > > >> =3D3D3D20 > > >> 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'help' in the Subject field > > > List technical documents are available at: > http://www.si-list.net > > 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 > 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 technical documents are available at: http://www.si-list.net 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