[SI-LIST] Re: [Negative Circuit elements?]
- From: Steve Corey <steven.corey@xxxxxxxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Mon, 04 Aug 2003 07:45:43 -0700
Se-Ho -- be careful with negative element values, since they can cause a
lot of problems. As you have stated, they can make your model
non-passive, and if so, it will blow up under some circumstances.
If you have complete control over how your model will be used (frequency
range and terminations), and you can show that it's stable (which is
weaker than passive) over that subset of terminations and frequency
range, then you're OK. Or, if you can prove that your model is passive
despite the negative elements, you're fine there as well.
As to why SPICEs accept negative elements -- simulators are differential
equations solvers, but not passivity checkers. Those elements
correspond to a valid set of differential equations, but not necessarily
a passive system.
-- Steve
-------------------------------------------
Steven D. Corey, Ph.D.
Time Domain Analysis Systems, Inc.
"The Interconnect Analysis Company."
http://www.tdasystems.com
email: steven.corey@xxxxxxxxxxxxxx
phone: (503) 246-2272
fax: (503) 246-2282
-------------------------------------------
You Se Ho wrote:
> To Dear all:
>
> Is it Ok to use negative RLCG values in Spice simulation for time
> domain and frequency domain simulation if I happen to have those negative
> circuit element values? Passivity is one possible reason that people say
> no that I can think of. I cannot find definite answer not using negative
> values. Anyway Pspice allows me to use those values, I think there is a
> reason for it.
>
> Thanks
> sincerely,
> se-ho You
>
>
>
>
> ------------------------------------------------------------------
> 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:
> //www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
> List archives are viewable at:
> //www.freelists.org/archives/si-list
> or at our remote archives:
> http://groups.yahoo.com/group/si-list/messages
> 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:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
