[SI-LIST] Re: Transmission line capacitance
- From: rahul kumar <rahul05kumar@xxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Sun, 25 Oct 2009 12:32:33 +0530
Hello all,
Thanks for the reply, i understood it. One more related point to clearify .
I am doing IO driver simulation running at frerquency less that 250
Mhz . Capacitive load at farend is given equal to 4pF along with
txline of 3cm. (Z0 = 50, Co = 1.5pF / Cm , Td = 60pS / cm )
1. Can i take equivalent capacitance to 4pF + (1.5pF *3) = 8.5pF for
my first order IO calculations. ( Transitions ) .
2. I am taking ELDO ( simulator ) lossless txline model which takes Z0
and Td as parameter. By doing this can i assume safely that i have
taken account of Transmission line capacitance of 4.5pF.
Or do i need to take lossy transmission line model and ask for more parameters.
Thanks for the help.
Rahul
<rtatikola@xxxxxxxxx> wrote:
> Rahul,
>
> Definitely not frequency dependent. The units show that it is dependent on
> the length of the transmission line and calculation is based on
> cross-section (2D approximation).
>
> Ramani
>
> On Sat, Oct 24, 2009 at 5:34 AM, rahul kumar <rahul05kumar@xxxxxxxxx> wrote:
>
>> Hello all,
>> I have seen in standards quoting transmission line capacitance equal to
>> 1.5pF per cm . How this number is calculated?
>> Is this value frequency dependent? transition dependent ?
>>
>> Kindly help.
>> Suggest link to know more information about the same.
>>
>> Thanks
>>
>>
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