Re: [SI-LIST] : MECL System Design Handbook

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From: Ritchey Lee (leeritchey@earthlink.net)
Date: Fri Jun 01 2001 - 10:09:57 PDT


Wolfgang,

The test board you cite doesn't relfect how real logic PCBs are built.
No one uses 100 mil wide traces. Also, no one builds PCBs with such
thick dielectrics. It would be misleading to suggest that what you
measure with the structures you have apply to the structures that appear
in logic PCBs, unless you show that the scaling is appropriate.

Lee

Dagostino, Tom wrote:

>
>
> I have a board that demostrates this very nicely. As soon as I get my
> scope/extraction system working again I will publish some results.
> The board is two layers with ground on one side and 50 Ohm traces on
> the other. Yes, these traces are quite wide, on the order of 0.100".
> There are several right angel bends with square corners. The corners
> are quite visible.
>
> Tom Dagostino
> Modeling Manger
> Mentor Graphics Corp.
> SAE
> tom_dagostino@mentor.com
> 503-685-1613
>
> -----Original Message-----
> From: Dr. Edward P. Sayre [mailto:esayre@nesa.com]
> Sent: Thursday, May 17, 2001 6:47 PM
> To: Ritchey Lee; Rich Peyton
> Cc: Roehrner Wolfgang; si-list@silab.eng.sun.com
> Subject: Re: [SI-LIST] : MECL System Design Handbook
>
> Lee and others:
>
> I don't know what kind of TDR or fixturing you might have used, but
> the
> excess capacitance is very real and can be seen. It is also
> illustrated in
> a number of microwave books. If your fixturing caused a significant
> loss (>
> 100 ps) of risetime of the step out of the TDR, then the capacitance
> effect
> will be washed out.
>
> Sincerely,
>
> ed sayre
> ==========================
> At 08:36 AM 5/10/01 -0700, Ritchey Lee wrote:
> >Any of you who want to know how the myth about right angle bends got
> >started, look
> >at figure 7.17 on page 155. This alleges that right angle bends can
> be
> >seen by a
> >TDR. I've done this measurement dozens of times and coiuld never see
> a right
> >angle bend.
> >
> >A few years ago, I called Mr. Blood the author of the book and asked
>
> >about the
> >diagram. His reply was that he knew the diagram was flawed, but
> there
> >wasn't time
> >to fix it before the book went to press.
> >
> >As a result, thousands of engineers have spend countless time
> worrying
> >about right
> >angle bends.
> >
> >When we publish technical information such as this, it is important
> to
> >insure it
> >is accurate.
> >This applies especially to applications notes, whic often contain
> entirely
> >false
> >data.
> >
> >Lee
> >
> >Rich Peyton wrote:
> >
> > > FYI,
> > >
> > > The hard copy can be ordered free of charge.
> > >
> > > Rich
> > >
> > > Roehrner Wolfgang wrote:
> > >
> > > > http://www.onsemi.com/home <http://www.onsemi.com/home>
> > > >
> > > > In the Menu-tree go to:
> > > >
> > > > Technical Documents
> > > > CD/Document Ordering
> > > > General Search
> > > >
> > > > search for document number: hb205
> > > > download it as pdf (or order!).
> > > >
> > > > regards,
> > > > Wolfgang
> > > >
> > > > -----Original Message-----
> > > > From: Ashok Babu K [mailto:k.ashokbabu@gdatech.co.in]
> > > > Sent: Tuesday, April 10, 2001 12:39 PM
> > > > To: si-list@silab.eng.sun.com
> > > > Subject: [SI-LIST] : MECL System Design Handbook
> > > >
> > > > Hi all,
> > > > I see that a good resource for general high speed termination
> design and
> > > > especially ECL/PECL termination is Motorola's MECL System Design
>
> > Handbook by
> > > > Blood Jr., and William R. Many articles and papers specify the
> same as a
> > > > good resource. Unfortunately I could not get the soft copy of
> the MECL
> > > > System Design Handbook. I could not get it from the ON
> Semiconductor
> > > > website. If any of you have the PDF file of the same or know
> where it
> > can be
> > > > obtained, please inform me. Any suggestions of other resources
> are highly
> > > > welcome.
> > > > Regards,
> > > > Ashok.
> > > >
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>
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+
> | NORTH EAST SYSTEMS ASSOCIATES, INC. |
> | ------------------------------------- |
> | "High Performance Engineering & Design" |
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+
> | Dr. Ed Sayre e-mail: esayre@nesa.com |
> | NESA, Inc. http://www.nesa.com/ |
> | Primrose Park Tel +1.978.392-8787 |
> | 5 LAN Drive, Ste 200 Fax +1.978.392-8686 |
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