A prefect case to use a simulations to judge between several choices. Use a 3D trool suca CST Microwave studio could be quite useful Hope this help Giancarlo ________________________________ Da: si-list-bounce@xxxxxxxxxxxxx per conto di CHUNG Yee Inviato: gio 08/03/2007 18.14 A: SI-List Oggetto: [SI-LIST] How to Route XFP 10G electrical trace? Hi all, I would like to get some opinions on how people route the electrical 10G traces. I am using FR4 and I don't plan no using any fancy via technologies such as blind via. I am looking into two options: 1, 100 ohm microstrip on top layer only, directly from the XFP connector to the PHY's BGA. However, it seems to me that this routing method is violated the XFP MSA spec in the figure 35 (XFP host board mechanical layout). I need to cut two gaps from the rear of cross-hatched area in order to escape the 10G signals and these signal will be covered by solder-mask. Based on internal discussion, we have some concern on the rear EMI gasket of the XFP cage that might scratch-off the solder-mask over time due to vibration hence short these traces to Gnd! However, I have check various vendors test board and even the Intel reference test board in the XFP MSA are using this method! 2, Use via to bottom layer and then 100 ohm microstrip on bottom layer to the PHY's BGA. Any feedback will be much appreciated! Yee ------------------------------------------------------------------ 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 <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 ************** Registrati ad Alice Basic e scarica Alice Messenger, il nuovo instant messenger che ti fa chattare GRATIS con i tuoi amici! <http://adsl.alice.it/servizi/alicebasic.html?pmk=psmail_foot01> ------------------------------------------------------------------ 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