[SI-LIST] Re: strip-line impedance

After reading my own response, I realize it's pretty ambiguous.  Doesn't
tell whether my conclusion is based on lack of negative knowledge, or
positive experience.

I recently had the opportunity to measure impedances of stripline traces
which run between ground and power planes.  I found that the TDR was
identical regardless of which plane I measured relative to.  After some
investigation, I concluded that for the geometries involved (only 14mils
between planes), the coupling between the planes was strong enough that,
AC-wise, they were one and the same.

The identical situation should hold true for your configuration, if your
planes are wide enough to have strong coupling between them and ground, and
the space between the 2 planes isn't wide enough to cause a discontinuity.

I prefaced the earlier mail with "As far as I know..." to allow the
possibility that I could be wrong - not an unheard of situation.

Jeff Loyer
(253) 371-8093


-----Original Message-----
From: Loyer, Jeff W [mailto:jeff.w.loyer@xxxxxxxxx]
Sent: Friday, October 19, 2001 2:21 PM
To: 'anthony@xxxxxxxxxxxxx'; si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: strip-line impedance
Sensitivity: Private



As far as I know...

Assuming your planes are very wide, and the space between the planes is kept
small, there shouldn't be any significant effect to Z0 at these geometries.

Jeff Loyer
(253) 371-8093


-----Original Message-----
From: Anthony Moulds [mailto:anthony@xxxxxxxxxxxxx]
Sent: Friday, October 19, 2001 10:04 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] strip-line impedance
Importance: High
Sensitivity: Private



A quick question:

An internal signal layer in a multi-layer stackup is situated between ground
and
a power plane. If the power plane splits into two islands is the effect
significant on the signal layer?  (Dielectric thickness between layers = 8
mil.)



Thanks.

Anthony Moulds.


------------------------------------------------------------------
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:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                http://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
  
------------------------------------------------------------------
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:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                http://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
  
------------------------------------------------------------------
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:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                http://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

Other related posts: