[SI-LIST] Re: fiber-weave effect alive and well?
- From: "Lee Ritchey" <leeritchey@xxxxxxxxxxxxx>
- To: "MARK HINTON" <mark.hinton@xxxxxxxxxxxxx>
- Date: Fri, 30 Nov 2007 15:20:14 -0800
By the way, why such wide traces?
Lee
> [Original Message]
> From: HINTON,MARK <mark.hinton@xxxxxxxxxxxxx>
> To: <leeritchey@xxxxxxxxxxxxx>
> Cc: si-list <si-list@xxxxxxxxxxxxx>
> Date: 12/1/2007 6:48:59 AM
> Subject: RE: [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
> > every designer concerned with 6 Gbps or higher differential serial
> data
> > communications channels on PCBs, backplanes, and single-ended skew
> > controlled parallel buses. Jeff's paper is real life, building upon
> > about 5 years of good research at Intel. The method that is used is
> > quite valid and will be seen in real designs. The Intel research is
> > able to better characterize weave skew using physical nyquist sampling
>
> > techniques. Yes, with different trace jogs you will see all sorts of
> > potential alignments, but in the worst case you will still find that
> > traces can have significant lengths of worst case fiber weave
> > alignment. If you are trying to design systems with 1000's of
> > differential pairs, there is a statistical certainty that one or more
> of
> > those pairs will have skew close to the absolute worst case, if not
> > designed to compensate for laminate weave anisotropy.
> >
> > The problem is most pronounced with weaves that have large holes
> without
> > fiber in the weave pattern, but you will also see issues with core
> > materials that are often constructed with large diameter fibers, like
> > 7628 material. The fiberglass the Lee proposes to use does have some
> > benefits, however, it does not totally eliminate the fiber weave
> > problem. It reduces it to a lower level. Unfortunately, it is not a
> > widely manufactured laminate weave.
> >
> > There are patented techniques for improving weave-induced skew, which
> > must be licensed. There are also some non-patented techniques, which
> > may also be used that are not quite as effective as the patented
> > techniques, but nevertheless can be used to design robust systems.
> > There is also some silicon IP that can be used to automatically
> > 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
> > >
> > >
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> =3D=
> > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=20
> > >
> > > Perry Qu=20
> > >
> > > Design & Qualification, Alcatel-Lucent Canada Inc.
> > >
> > > 600 March Road, Ottawa ON, K2K 2E6, Canada=20
> > >
> > > DID: 613-7846720 Fax: 613-5993642=20
> > >
> > > Email: perry.qu@xxxxxxxxxxxxxxxxxx=20
> > >
> > >
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> =3D=
> > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=20
> > >
> > > =20
> > >
> > >
> > >> -----Original Message-----
> > >> From: si-list-bounce@xxxxxxxxxxxxx=20
> > >> [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of=20
> > >> Aubrey_Sparkman@xxxxxxxx
> > >> Sent: Friday, September 14, 2007 1:59 PM
> > >> To: leeritchey@xxxxxxxxxxxxx; rdudek@xxxxxxxxxxxxxxx;=20
> > >> si-list@xxxxxxxxxxxxx
> > >> Subject: [SI-LIST] Re: fiber-weave effect alive and well?
> > >> =20
> > >> Would you like to share a link?=3D20
> > >> =20
> > >> =20
> > >> Aubrey Sparkman=3D20
> > >> Enterprise Engineering Signal Integrity Team=3D20 Dell,
> Inc.=3D20=20
> > >> Aubrey_Sparkman@xxxxxxxx=3D20
> > >> (512) 723-3592=3D20
> > >> "Discovery consists of seeing what everybody has seen and=20
> > >> thinking what nobody else has thought." - Jonathan Swift
> > >> =20
> > >> =20
> > >> -----Original Message-----
> > >> From: si-list-bounce@xxxxxxxxxxxxx=20
> > >> [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?
> > >> =20
> > >> We already have a glass weave solution. Check my column in=20
> > >> the April issue of Circuitree magazine.
> > >> =20
> > >> Lee Ritchey
> > >> =20
> > >> =20
> > >>
> > >>> [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,
> > >>> =3D20
> > >>> I agree, Fiber Weave Effect (FEW) has most certainly been=20
> > >>>
> > >> confirmed by
> > >> such
> > >>
> > >>> research. However, there is a new change in the wind. I=20
> > >>>
> > >> have the=3D20=20
> > >>
> > >>> unique opportunity, as a technical liaison, to enable a=20
> > >>>
> > >> technology=3D20=20
> > >>
> > >>> that may put
> > >>>
> > >> an
> > >>
> > >>> end to FWE as a consideration in high-speed designs. We=20
> > >>>
> > >> all know that
> > >> =20
> > >>
> > >>> the crux of the matter is the glass weave and its effect on=20
> > >>>
> > >> localized
> > >> Er.
> > >>
> > >>> Either get ride of the reinforcement layer completely or
> more=3D20=20
> > >>> challenging change the fundamentals of the glass weave fabrication
> > >>>
> > >> process (GWFP).
> > >>
> > >>> =3D20
> > >>> We have taken the more challenging (and fun) approach and have=20
> > >>> rocked=3D20 the fundamentals the GWFP. I cannot disclose much
> the=20
> > >>> specifics of=3D20 the technology and our partners in such an=20
> > >>>
> > >> open forum. =20
> > >>
> > >>> However, if=3D20 you are interested learning more feel free=20
> > >>>
> > >> to contact=20
> > >>
> > >>> me and we can=3D20 get the proper NDAs in place to facilitate=20
> > >>>
> > >> such a discussion.
> > >>
> > >>> =3D20
> > >>> RD
> > >>> =3D20
> > >>> Russell Dudek
> > >>> Technology Specialist
> > >>> Compunetics, Inc.
> > >>> 700 Seco Road
> > >>> Monroeville, PA 15146
> > >>> 412-858-6264
> > >>> rdudek@xxxxxxxxxxxxxxx
> > >>> www.compunetics.com <http://www.compunetics.com/> =3D20
> > >>>
> > >>> To see where no one notices the contrast of white on white is =
> > >>>
> > > an=3D20=20
> > >
> > >>> indispensable virtue of infinite potential.
> > >>>
> > >>> =3D20
> > >>>
> > >>>
> > >>>
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