[SI-LIST] Re: How to properly simulate signal integrity across PCBs interconnected by Flex?

  • From: "Kotson, Michael" <mkotson@xxxxxxxxxxx>
  • To: <jeanpierrepoulin@xxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
  • Date: Tue, 4 Sep 2007 12:29:18 -0600

Hi Jean-Pierre,
   We regularly use flex cables in our designs which must be qualified
for MIL-STD EMI levels (much tougher than FCC), so I really don't think
you will have much issue.  Follow the same design guidelines that you
would for a rigid PCB (continuous return path, minimize reflections,
etc).  Samtec does a great job of providing spice connector models for
flex-type connectors.  Most any simulation package will handle this kind
of scenario, but I personally use Hyperlynx due to its simplicity.  One
word of caution however, polyimide (the dielectric used to make flex
circuits) can be _VERY_ lossy at higher frequencies.  Always check the
loss tangent of the polyimide manufacturer you plan to use, as I've seen
a wide range in this number from various manufacturers.

Best of luck to you,
-Mike

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On Behalf Of jeanpierrepoulin
Sent: Friday, August 31, 2007 2:04 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] How to properly simulate signal integrity across PCBs
interconnected by Flex?

Hello Gurus,

I am attempting to correctly design the first time a system=20
consisting of five small PCBs interconnected by short (1-5 inch) Flex=20
cable.  While most signals are single ended and of moderate speed (20-
80 Mhz and with most edges controlled by the driving strength of FPGA=20
drivers), I am particularly concerned about some clock signals that I=20
need to spread to all these PCBs and wish to properly simulate...

1. Is there a flex connector vendor in particular that publishes=20
quality IBIS model the simulating software will need?

2. What simulating software do you recommend as easiest to use for=20
this type of need?

3. Do you think usage of Flex cabling in this fashion would cause =20
problems during FCC certification?

4. Any good web site / publication you've seen on the subject of=20
signal integrity across Flex cabling?

Any hint you could offer is greatly appreciated!!

   Jean-Pierre Poulin


------------------------------------------------------------------
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 technical documents are available at:
                http://www.si-list.net

List archives are viewable at:    =20
                //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
 =20


*****************************************************************
*************
CONFIDENTIAL NOTE: This e-mail and any attachments may be 
confidential and protected by legal privilege. If you are not 
the intended recipient, be aware that you are hereby notified 
that any unauthorized review, use, disclosure, dissemination, 
distribution, or copying of this communication, or any of its 
contents, is strictly prohibited. If you have received this 
email in error, please notify us immediately by replying to the 
sender and deleting this copy and the reply from your system. 
Thank you for your cooperation. 

EXPORT CONTROLLED DOCUMENT 
This document may contain information whose export is restricted 
by the Arms Export Control Act (Title 22, U.S.C., Sec 2751 Et 
Seq.) or the Export Administration Act of 1979, as amended, 
(Title 50, U.S.C., App. 2401, Et. Seq.) Violations to these 
export laws are subject to severe criminal penalties.  

All technical data forwarded by VT Miltope to its suppliers is 
EXPORT CONTROLLED. Supplier shall not disclose technical data in 
any form to a Foreign Person (including foreign person employees 
of Supplier), or export the technical data from the United 
States without U.S. Government authority and the written 
authorization of VT Miltope Contracts Department. 
*****************************************************************
*************
------------------------------------------------------------------
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 technical documents are available at:
                http://www.si-list.net

List archives are viewable at:     
                //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: