[SI-LIST] Re: impedance determination of a perticular interface.....

  • From: bala <balaseven@xxxxxxxxx>
  • To: malli.1729@xxxxxxxxx
  • Date: Thu, 18 Sep 2014 10:25:02 +0530

50 ohm is the compromise between power handling(low impedance) and low
insertion loss( high impedance).
Regards
bala
On 18 Sep 2014 10:09, "Mallikarjun K" <malli.1729@xxxxxxxxx> wrote:

> Hi,
> I have seen specifying routing impedance of interfaces from Manufacturers
> like for
>
> USB Differential impedance of 90 ohms
>
> DDR2 Single ended impedance 50-60 Ohms, Differential impedance - 100-120
> Ohms.
>
> If not specified , generally we will try to take it as 50 Ohms.
>
> Based on this interface impedance levels, we will design corresponding
> Stripline/microstrip lines parameters like Height above reference plane and
> width to give required characterstic impedance..
>
> What drives these characteristic impedance values? Whether the drivers
> output impedance has any affect on this...?
>
> If route a 50Ohms interface with 20 Ohms impedance what are the impacts?
>
> In few papers, i have read that intentionally designers will route with
> higher/lower (not sure ) impedance for crosstalk reduction. Is this
> impedance has any relationship with the impedance....
>
>
> ------------------------------------------------------------------
> 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:
> http://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:
>                 http://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:
http://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:     
                http://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: