Quite a few posts mentioned about 3D full wave simulation on this, but what you get from that is the insertion loss for the link. How will that tell you whether you have acceptable eye or not at receiver ? On MSA spec it mentioned that we need to have IL< 9.6dB at 5.5GHz and for a short run on microstrip with or without via, the IL won't be no where near that number. What 3D sim can tell is how IL of one scheme perform against another but it won't tell whether the good one is good enough. To close the loop, we really need to do some time domain simulation with Tx/Rx Spice model and get the eye diagram at the receiver. The problem is no XFP vendor seems to provide any models for their device. Regards Perry =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=20 Perry Qu=20 Design & Qualification, Alcatel-Lucent Canada Inc. 600 March Road, Ottawa ON, K2K 2E6, Canada=20 DID: 613-7846720 Fax: 613-5993642=20 Email: perry.qu@xxxxxxxxxxxxxxxxxx=20 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=20 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Javier DeLaCruz Sent: Friday, March 16, 2007 1:55 AM To: SI-List Subject: [SI-LIST] Re: R: How to Route XFP 10G electrical trace? I agree that you will have a hard time getting this to work properly without some full-wave simulation. Given that you are routing on the top layer, you will have the benefit of less dialectic loss from the air above the PCB. Having this in microstrip does take up slightly more space since you typically need to have wider traces to achieve an certain impedance as compared to stripline. That hurts if it is a high density design but it helps otherwise since the variation in etching should have less of an effect on a wider trace as a percentage. Additionally, the lower dielectric loss of microstrip mode (assuming air and thin soldermask above it) will help as I mentioned earlier. The fact that you are not going through a via in option 1, will help. Vias always pose a significant discontinuity unless you use expensive via design rules, so I would avoid your second option. I want to avoid giving a rule of thumb on this since it is dangerous to use such a rule at 10G, but you should plan on having many shielding vias adjacent to the traces to your power supplies. Self resonance of the transmission lines is something to watch out for at these frequencies. Plan on simulating this, or outsourcing this simulation since the software can be pricey. Regards, Javier DeLaCruz =3D20 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Whitehead Sent: Friday, March 09, 2007 2:47 PM To: SI-List Subject: [SI-LIST] Re: R: How to Route XFP 10G electrical trace? I would definitely kick off a simulation effort. Keep in mind that with microstrips it is much harder to control the impedance of those outer-layer traces, in the fabrication process. Also, care should be taken if routing through the ground area on the top layer and when going under the the cage; both are opportunities for impedance discontinuities. Cheers, Jim -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of gianguida@xxxxxxxx Sent: Friday, March 09, 2007 1:28 AM To: Yee.Chung@xxxxxxxxxxxxxxxxxx; SI-List Subject: [SI-LIST] R: How to Route XFP 10G electrical trace? 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/>=3D3D20 List archives are viewable at: =3D3D20 //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 =3D3D20 ************** 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=3D3D3Dpsmail_foot01>=3D= 3D2 0=3D ------------------------------------------------------------------ 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: =3D3D20 //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 =3D3D20 ------------------------------------------------------------------ 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: =3D20 //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 =3D20 ------------------------------------------------------------------ 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 ------------------------------------------------------------------ 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