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