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June 2005

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Subject:
From:
Dave Seymour <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Dave Seymour <[log in to unmask]>
Date:
Wed, 8 Jun 2005 10:25:50 -0400
Content-Type:
text/plain
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text/plain (80 lines)
Ken,

When designing a  PCB, the engineers talk about "Stubs" as a "T" in the
signal route.


o------------o------------o   This is daisy chain.

o------------o-----------o
                     |
                     |
                     |
                     o                             This is a "Stub" or "T".


Depending on the frequency ( rising edge) of the signal, reflections could
create false triggering of the circuit.

Stubs are impossible to design out 100%, think about pin escapes,  or
wire bonds
on the IC itself.  However, the length of the stub is can be critical.

Do some google searches on signal integrity or high speed design.

Hope this helps,

Dave




Dave Simonik wrote:

>Could this be referencing the plated hole wall remaining above the Must Not
>Cut (MNC) layer after Back Drilling on back planes? This is normally
>referred to as the 'Stub'.
>
>Dave Simonik
>Sanmina SCI
>Owego NY Division
>
>-----Original Message-----
>From: Kanaiyalal Patel [mailto:[log in to unmask]]
>Sent: Wednesday, June 08, 2005 9:54 AM
>To: [log in to unmask]
>Subject: stubbing in circuit design?
>
>
>All,
>What is stubbing in PCB circuit design? Can some one
>send me a picture or link to visulize it?
>
>Re,
>Ken Patel
>
>
>

--
Dave Seymour, CID+
Catapult Communications Inc.
800 Perimeter Park Dr, Suite A
Morrisville, NC 27560

Direct: (919)653-4249
Main: (919)653-4180
Fax: (919)653-4297

[log in to unmask]

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