[SI-LIST] Re: Seperate Sparameter for gnd & supply plane !!
- From: Rajesh K <rajeshk0212@xxxxxxxxx>
- To: steve weir <weirsi@xxxxxxxxxx>
- Date: Fri, 3 Jun 2011 06:48:43 +0530
you are very much correct, one VDD or ten VDD doesn't matter. it all matters
potential difference. This is universal truth, we are not debating here this
point. The question is, how should I get or generate separate s-parameter
for VDD, VSS domain in a typical die, package, pcb connected system. This is
purely from simulation point of view. I wish to probe(in simulation) VSS
noise at different point in package, pcb, die input. if I use typical
s-parameter, VSS of package, pcb & die will be lumped together. Therefore, I
will not be able to estimate VSS noise at different point.
please do not expect to write new EM tool which will need to search for
equipotential point. suggest some solution within existing set of EM tools
available in market
On Fri, Jun 3, 2011 at 6:28 AM, steve weir <weirsi@xxxxxxxxxx> wrote:
> **
> One Vdd, or ten Vdd's, does not matter. AC and DC current will result in
> voltage potentials through interconnects. Vss at any two points on a die,
> PCB plane, or different planes in a stack-up will have different absolute
> potentials. The issue is: you need to understand what that potential
> difference is in reference to, or perhaps more importantly, what it is
> common to, and therefore whether it matters. If you were to probe a given
> signal or power rail, think about where would you ideally put the ground
> side of your scope probe, and why you would put it there.
>
> Steve.
>
>
> On 6/2/2011 5:11 PM, Rajesh K wrote:
>
> in a system with multi-voltage power rail, where VSS is common to all the
> power rails. any noise on VSS will impact system performance differently.
> you will get different results if you assume VSS quiet/noisy. separate
> s-parameters of power & VSS are highly desirable in such scenario.
>
>
>>
> --
> Thanks
> Rajesh
>
>
>
> --
> Steve Weir
> IPBLOX, LLC
> 150 N. Center St. #211
> Reno, NV 89501 www.ipblox.com
>
> (775) 299-4236 Business
> (866) 675-4630 Toll-free
> (707) 780-1951 Fax
>
>
>
--
Thanks
Rajesh
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