FreeLists / si-list / [SI-LIST] Re: High Speed PCB design standards

["Lee Ritchey" <leeritchey@xxxxxxxxxxxxx>]

All,

For quite some time, I sat on the committee that was responsible for
revising the spec to its current form.  I pointed our many areas in the
document that were not accurate and was unable to get them changed.  As a
result, I stopped working with that group.

I should also point out that I spoke at length with some of the leaders at
IPC on the need to be rigorous in the creation of documents such as this,
again to no avail.

Those who choose to use this document should know that the committee that
revised were all volunteers who were unpaid as well as unscreened as to
their qualifications to revise this document.  I don't mean to downplay
their hard work, but what I witnessed was quite a bit of leaving in the
legacy stuff from the original version of the spec on the premise that it
must be right or else it would not have been put there in the first place.

I pointed out that many users of this document were going to be new
engineers who would trust it to be accurate and, therefore, needed to be
rigorously reviewed to insure it was truly accurate.  To say, that it is
just a guideline and leave in items that are known to be wrong or suspect
is not right.  Anywhere there is a rule of thumb or an estimate instead of
real analytical work to support a concept is bad for us all.  It means we
won't know when we can trust a document and when we can't.   That's the way
most application notes are and it is wrong to do more of it.

If Nick sees this as denigration of the work, the proper response is to
take steps to insure the accuracy of the documents that are published.

I have a very large pile of markups from my work on this document if anyone
wants to see them.

It is not my intention to slam anyone's  work, but I made a commitment to a
large number of students to respond when I felt something needed it and
this is a document that needs such a response.

If one wants to get right down to the basics, the IPC is concerned with
fabrication and assembly of PCBs and does that very well.  Stretching that
to publishing documents on high speed design goes too far.  That is simply
not its expertise.

For those on the review committee who see this as a slam, I apologize if it
hurts your feelings, but we must be more rigorous when we are responsible
for a document that will circulate worldwide and be taken as accurate. 
Imagine if civil engineering documents were done this way and bridges fell
in the bay due to poor guidance.  We would surely not tolerate that.  Why
should we tolerate it in electrical engineering?

Lee W. Ritchey
Speeding Edge
P. O. Box 2194
Glen Ellen, CA 95442
Phone- 707-568-3983
FAX-    707-568-3504

I just used the energy it took to be angry to write some blues.
Count Basie


> [Original Message]
> From: Scott McMorrow <scott@xxxxxxxxxxxxx>
> To: <paulter@xxxxxxxx>; silist <si-list@xxxxxxxxxxxxx>
> Date: 7/7/2004 11:13:29 AM
> Subject: [SI-LIST] Re: High Speed PCB design standards
>
> Nick,
>
> Unfortunately, since this is not a document available for free 
> distribution, it would be impossible for someone like myself to clarify 
> the claims of either Lee or yourself, without purchasing the document.   
> It may be the Lee is referring to the previous version.  It would be 
> interesting if Lee would be able to clarify his complaints with you 
> off-line and then have either one of you report back on whether there 
> are any remaining issues. 
>
> If there is good information in the document, it needs to be known.  If 
> the information is not good, then this should be clarified in a public 
> forum such as ours.  This in no way denigrates the work of those 
> involved in the formulation of IPC-2141A.
>
> best regards,
>
> scott
>
>
> -- 
> Scott McMorrow
> Teraspeed Consulting Group LLC
> 121 North River Drive
> Narragansett, RI 02882
> (401) 284-1827 Business
> (401) 284-1840 Fax
> (503) 750-6481 Cellular
> http://www.teraspeed.com
>
> Teraspeed is the registered service mark of 
> Teraspeed Consulting Group LLC
>
>
>
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