[SI-LIST] Re: doubt in lossless transmission line funda

  • From: istvan Novak <Istvan.Novak@xxxxxxx>
  • To: Canes Venatici <starsilic@xxxxxxxxx>
  • Date: Wed, 17 Sep 2008 09:09:37 -0400


It depends on what degree of correlation you are looking for and what 
values you plug in.  When the extra rise time due to capacitive loading 
is small, the correlation may be good.  With heavy capacitive load, 
however, the electrical length of the line does matter because you 
essentially have an LC resonator, where L the the Zo*tpd inductance of 
the transmission line and C is your load capacitance. Eventually the 
source impedance may matter as well.


Istvan Novak
SUN Microsystems

Canes Venatici wrote:
> Hi all,
> I was driving a lossless transmission line with a near-end rise time of 'tr' 
> (10-90% of Vdd) with an amplitude of Vdd .
> The far-end was loaded with capacitance load. While evaluating the far-end 
> transition times the expected  rise time  (10-90% of Vdd)
> is sq.rt(square(tr) + square(2.2*Z0*Cload)). Spice simulation results are not 
> correlating with the formula. 
> Is there an error in my formula??? Please help!
> Regards,
> Canes

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:

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List technical documents are available at:

List archives are viewable at:     
or at our remote archives:
Old (prior to June 6, 2001) list archives are viewable at:

Other related posts: