[SI-LIST] Re: termination resistor

  • From: Tesla <emcesd@xxxxxxx>
  • To: bertsimonovich@xxxxxxxxxx
  • Date: Mon, 24 Dec 2012 09:15:41 +0800 (CST)

Hi,
 
How could it be that--Driver impedance varies somewhat with load? it should be 
a contant value if the circuit is decided.
 
Thanks.
 
Tesla







At 2012-12-24 08:06:53,"Lambert Simonovich" <bertsimonovich@xxxxxxxxxx> wrote:
>Because the driver is a semi-conductor, it's output impedance could vary
>based on rising/falling edge transitions, manufacturing process (slow,
>typical, fast), and the load it is driving. One way to estimate the driver's
>impedance is by using an IBIS model of the device. Since IBIS models are
>ASCII based, you can simply use your favourite text editor to view and
>quickly estimate the output impedance when driving 50 Ohms by using two of
>the four V-T waveform tables.
>
>Here is the link to one of my blog postings, I did a while back titled,
>"Determining Output Impedance from IBIS".
>
>http://blog.lamsimenterprises.com/2010/12/22/drivers-output-impedance-from-i
>bis/
>
>Bert Simonovich  
>LAMSIM Enterprises Inc.
>Web Site: http://lamsimenterprises.com
>Blog: http://blog.lamsimenterprises.com/ 
>
>-----Original Message-----
>From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
>Behalf Of XiaoLiang Tan
>Sent: December-22-12 10:02 PM
>To: si-list@xxxxxxxxxxxxx
>Subject: [SI-LIST] termination resistor
>
>Dear Expert,
>         Hello, I am designing a high speed system.Since I don't know my
>driver's output resistance, thus the termination resistor value is not
>known. Thus may I use the variable resistor? If I use the variable resistor,
>the size is big thus I am unable to put all the resistor near the driver.( I
>have more than 10 outputs needs to be terminated). Which means the
>termination resistor could not be put close to the drivers.
>         However, if I use a fixed and small size resistor, I need to trim
>the resistor manually when I doing the testing.
>         So may I know that which one is more suitable? Thanks.
>--
>Best Regards
>
>==================================
>*Xiaoliang, Tan*
>*
>*
>
>
>------------------------------------------------------------------
>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 forum  is accessible at:
>               http://tech.groups.yahoo.com/group/si-list
>
>List archives are viewable at:     
>               //www.freelists.org/archives/si-list
> 
>Old (prior to June 6, 2001) list archives are viewable at:
>               http://www.qsl.net/wb6tpu
>  
>
>
>
>-----
>No virus found in this message.
>Checked by AVG - www.avg.com
>Version: 2013.0.2805 / Virus Database: 2637/5976 - Release Date: 12/21/12
>
>------------------------------------------------------------------
>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 forum  is accessible at:
>               http://tech.groups.yahoo.com/group/si-list
>
>List archives are viewable at:     
>               //www.freelists.org/archives/si-list
> 
>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 forum  is accessible at:
               http://tech.groups.yahoo.com/group/si-list

List archives are viewable at:     
                //www.freelists.org/archives/si-list
 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu
  

Other related posts: