[SI-LIST] Re: [Help] How to do termination in differential signal with series termination ?

  • From: "DAVID CUTHBERT" <telegrapher9@xxxxxxxxx>
  • To: "steve weir" <weirsi@xxxxxxxxxx>
  • Date: Fri, 5 Dec 2008 03:10:15 -0700

Steve,
in my haste I was thinking double termination ah la video. You are right.
Nothing needs to be done at the driver.

   Dave


On 12/4/08, steve weir <weirsi@xxxxxxxxxx> wrote:
>
> Parallel terminations absorb energy at the far end and is related only
> to the channel, not the driver Z.    Also, you've got your impedances
> backward.
>
> Steve.
> King Da wrote:
> > Hi,Folks,
> > I have a differential pair which odd mode impedance is 48 Ohm and even
> mode
> > impedance is 108 Ohm by TDR measurement.
> > I would like use 100 Ohm for differential termination at far end, but how
> to
> > choose series termination resistor for each trace at near end?
> >
> > I refered Bogatin's "Signal Integrity:Simplified" book that said parallel
> > termination R2 equal Zeven, So, I should use 108 Ohm subtract 20 Ohm of
> my
> > driver's Ro is 88 Ohm for my series termination at near end, am I right?
> >
> > The Rseries = 108 (Zeven) - 20 (Driver's Ro) = 88 Ohm, right ?
> >
> > Does the differential termination resistor is 100 Ohm better than 91Ohm ?
> >
> > Thanks,
> >
> > Yardala
> >
> >
> > ------------------------------------------------------------------
> > 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
> >
> >
> >
> >
>
>
> --
> Steve Weir
> Teraspeed Consulting Group LLC
> 121 North River Drive
> Narragansett, RI 02882
>
> California office
> (866) 675-4630 Business
> (707) 780-1951 Fax
>
> Main office
> (401) 284-1827 Business
> (401) 284-1840 Fax
>
> Oregon office
> (503) 430-1065 Business
> (503) 430-1285 Fax
>
> http://www.teraspeed.com
> This e-mail contains proprietary and confidential intellectual property of
> Teraspeed Consulting Group LLC
>
> ------------------------------------------------------------------------------------------------------
> Teraspeed(R) is the registered service mark of Teraspeed Consulting Group
> LLC
>
> ------------------------------------------------------------------
> 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
>
>
>


------------------------------------------------------------------
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: