Re: Package Model?

Zheng SHI writes:

> Hi, Ibis folks:

> Thank you all for reading and answering my last question
> about Polarity and Enable sub-param. This time I met another
> problem, an I/O pin has a package model as below:

> INT------ o----/\/\/\----o----/\/\/\----o------ EXT
> | | |
> o----@@@@@@@---o----@@@@@@@---o
> | | |
> | | |
> === === ===
> | | |
> | | |
> GND GND GND

> It doesn't fit the default ibis package model, so I can't
> choose the R_pkg, L_pkg and C_pkg. Still, I can't find
> ways using [Define Package Model] to deal with it.

It appears from the schematic that the purpose of the
resistors in parallel with the inductors is to approximately
model a skin-effect resistance. One possibility here is
to model the pins as transmission lines (without the resistors)
and use a simulator that handles skin-effect directly.

I suggest you analyze the behavior of this network at
frequencies up to ~5/rise-time and see if the resistors are
actually needed to get the results you need.

Since your schematic does not include values my comments are
only a guess at the purpose.

Christopher Reid
Interconnectix
Received on Thu Dec 12 09:43:35 1996