Hi Gopalakrishnan, If you are using source termination, the resistor value should be the difference between the trace characteristic impedance (Zo) and the driver output impedance (Zout): Termination resistor = Zo - Zout. Theoretically, the signals will be fully absorbed at the driver after one round trip time. Anyway, I found that the output impedance is not a constant value. From my experience, termination resistor with 22-47ohm will absorb most of the ringing. -- Regards, Chai >From: "Gopalakrishnan Sethuraj" <gopalakrishnan.sethuraj@xxxxxxxxx> >Reply-To: gopalakrishnan.sethuraj@xxxxxxxxx >To: <weirsp@xxxxxxxxxx>, <si-list@xxxxxxxxxxxxx> >Subject: [SI-LIST] terminator resistor >Date: Mon, 2 Dec 2002 09:03:49 +0530 > >hai > >how to find out the terminator resistor value when the ringing is occur in >high speed signal transmission line.could you let me know.is there any >specfic formula to find the terminator value? > >Thanks&Regards >Gopalakrishnan.S _________________________________________________________________ Protect your PC - get McAfee.com VirusScan Online http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963 ------------------------------------------------------------------ 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 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