Al
This is the book on the theory
http://www.amazon.com/Microstrip-Slotlines-Edition-Microwave-Library/dp/1608075354
For ENIG dispersion, you can go to some of the work the Yuriy and I did a
few years ago.
http://www.simberian.com/Presentations/NickelCharacterizationPresentation_emc2011.pdf
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber`38368&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F6030003%2F6038267%2F06038368.pdf%3Farnumber%3D6038368
Scott
Scott McMorrow
Consultant - R&D
Teraspeed Consulting - A Division of Samtec
16 Stormy Brook Rd
Falmouth, ME 04105
(401) 284-1827 Business
http://www.teraspeed.com
On Thu, Jul 2, 2015 at 11:48 AM, Alfred P. Neves <al@xxxxxxxxxxxxxxxxx>
wrote:
Thanks Scott. I need to learn more about this issue since we want to
intentionally place dispersive channels on one of our Serial Link Platforms
for 32-56Gbpsec.
- Al
*Products for the Signal Integrity Practitioner*
*Alfred P. Neves*
Chief Technologist
Office: 503-679-2429
*www.wildrivertech.com* <http://www.wildrivertech.com/>
*2015 Best In Design&Test Finalist*
On Jul 2, 2015, at 8:30 AM, Scott McMorrow <scott@xxxxxxxxxxxxx> wrote:
Al
Microstrip dispersion is pretty much a non-issue, if, and only if:
1) trace geometry is small so that the microstrip is not close to exciting
an additional trace/plane mode
2) the microstrip is not ENIG or ENEPIG plated.
In general, production boards cannot use the non-lossy platings like
silver, due to environment concerns (they are fine for test boards0, as a
result, either a nickel barrier plating is used, or some form of
soldermask. These, of course, cause significant dispersion, when compared
to stripline.
regards
Scott
Scott McMorrow
Consultant - R&D
Teraspeed Consulting - A Division of Samtec
16 Stormy Brook Rd
Falmouth, ME 04105
(401) 284-1827 Business
http://www.teraspeed.com
On Thu, Jul 2, 2015 at 11:17 AM, Alfred P. Neves <al@xxxxxxxxxxxxxxxxx>
wrote:
Based on measurements and simulations (we use Simbeor THz) using our
ISI-32 loss platform (includes both microstrip and stripline) the
dispersive nature of microstrip barely rears its head even at 32Gbpsec.
My guess folks believe the microstrip dispersion is an issue and it is
really poor launch design and/or weave issues. De-embedding issues also
creates group delay noise which is misinterpreted as dispersion.
Donât mean to be critical but this thread is all over the map. The
original question suggests a return to basic signal integrity practice.
I would suggest focusing on data mining both the SE and DIFF s-parameters
and relate resonances to quarter and half wave topological features in the
channel. Also, did you also validate your VNA calibration with simple
standards like broadband load in each port, and a THRU for each
transmission path? Problems with VNA set up often creates single
resonances (often occurs when an adapter has an issue). Confirm trace
impedances. Use a TDR and juxtapose that to SE return losses. Focus on
connectors, VIAS, and anything any pathology a fraction of an inch long.
- Al
Products for the Signal Integrity Practitioner
Alfred P. Neves
Chief Technologist
Office: 503-679-2429
www.wildrivertech.com <http://www.wildrivertech.com/>
2015 Best In Design&Test Finalist
On Jul 2, 2015, at 7:50 AM, Doug Brooks <dbrooks9@xxxxxxxxxxxxxxx>
wrote:
Wow. Thanks for the input. That seems like a big difference.
Doug
Jeff Loyer SI wrote:
Hi Doug,
FYI, my experience (and others') agrees with Gert's, that PCB "copper"
isn't
pure. Our measured conductivities were:
⢠2.1uohm-cm (4.76e7 ohm-m conductivity) for stripline
⢠2.4uohm-cm for microstrip
Copper = 1.7uohm-cm (5.88e7 ohm-m)
We measured the temperature coefficient as 0.35%/degree C (interestingly
there was a difference between U.S. domestic and foreign vendors').
Coming from the copper foil vendors, IPC specs. ensure it is very
"pure",
with conductivity specified. It appears the processing of the laminate
suppliers affects the conductivity significantly, though we've never
understood exactly what part of the process does that. I suspect
treatments
diffuse into the copper, reducing its conductivity.
The data Iâve seen indicates packagesâ copper behaves more like copper.
Jeff Loyer
Signal Integrity Consulting
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On
Behalf Of Doug Brooks
Sent: Wednesday, July 1, 2015 8:44 PM
To: SI-LIST
Subject: [SI-LIST] Re: Resistivity of copper
Thank you all for your help.
Turns out I was on the wrong track! First, I have been under the
assumption
that the resistivity curve was non-linear over this wide a range. Turns
out
that the normal equation still works here. ( Rho-subT
= Rho-sub20*(1 + Alpha-sub20*(T-20)) This leads to about 5.3 or 5.1
depending on what assumptions you make. My 4.3 number, it turns out, was
irrelevant!
So, I apologize for the exercise. But thanks for the support.
Doug Brooks
Doug Brooks wrote:
I would like to know the resistivity of copper at 540 degrees C,
assuming it is 1.72 * 10^-8 Ohm*m²/m at 20 degrees C. The temp
coefficient of resistivity is .00393 at 20 degrees C but using this I
get a result of around 5.31 at 540 degrees. But a problem I am solving
says it is closer to 4.30. I am having trouble resolving the
difference.
Can anyone confirm the (approx.) 4.3 number for me?
Thanks for any help.
Doug Brooks
------------------------------------------------------------------
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:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
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:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
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:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
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:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
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:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
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:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
