[SI-LIST] Re: Lumped capacitance estimation
- From: steve weir <weirsi@xxxxxxxxxx>
- To: sushil.gupta@xxxxxx, si-list@xxxxxxxxxxxxx
- Date: Wed, 06 Apr 2005 05:53:31 -0700
Sushil, you can calculate the capacitance from geometry or w/ a 2D
solver. However, assuming that 3" of trace will behave as a lumped load to
an average ( its the min that matters ) Tr / Tf of 600ps won't be very
accurate as you will definitely see some wave effects. If you are just
looking at one I/O w/o regard to SSO, then take your pick: IBIS or SPICE
whichever you have an accurate model for.
Steve.
At 05:42 PM 4/6/2005 +0530, Sushil Kumar GUPTA wrote:
>Hi all,
> I need to calculate equivalent lumped capacitance seen by an IO
> driver which is connected to PCB trace (approx 3 Inches) and then cable.
> The average rise/fall time is 600ps. I have information about the PCB
> trace capacitance/inches. Will my assumption be correct if I take
> PCB-trace length (for lumped-capacitance calculation) which provides
> 300ps delay.
> What would be the best way to simulate IO driver as far
> as rise/fall time accuracy is concerned assuming lumped model for Tx line.
>
>Thanks
>sushil
>
>====================================================
>Beat indecision and you beat the clock.
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