RE: Package Parasitics

In addition to other reasons...

We have often found this section of the IBIS model to be inadequate in
describing our CPU and chipset packages. For example, there is no way to
include a transmission line element of any sort. We usually use a Package
Model or an Electrical Board Description (EBD) to more accurately describe
the package. (Both are part of the IBIS specification.) In those cases we
will set R_pkg, L_pkg, and C_pkg to zero.

I hope that helps.
Kerry
Intel Corp.

 -----Original Message-----
From: Mark Bossard [mailto:mbossard@atmel.com]
Sent: Wednesday, April 25, 2001 6:10 AM
To: Syed Huq
Cc: r6aabt@email.sps.mot.com; ibis-users@eda.org
Subject: Re: Package Parasitics

I agree with Syed...

The ASIC house I work in does supply ibis models to our customers that
are simply an ibis model for one I/O buffer. They are many times left
without package RLC so they can be filled in depending on the package
that is used.

-Mark Bossard
Atmel Chesapeake Design Center

Syed Huq wrote:
>
> One reason could be is that a ASIC vendor is simply creating "buffer only"
> models without any package parasitics. Once the ASIC is defined(with
package)
> then you create the full IBIS model with all the individual buffers along
> with the package parameters..
>
> For a commercially available component, it does not make sense to have
> a model without the package parasitics.
>
> Syed
> Cisco Systems, Inc
>
> >
> > > |
> > >
> > > I have found other models that have these values set to zero:
> > >
> > >
> > > > > > [Package]
> > > > > > R_pkg 0 0 0
> > > > > > L_pkg 0 0 0
> > > > > > C_pkg 0 0 0
> > >
> > > Can you explain why these values are used, i.e. why the model would be
> > > realistic with no package parasitics?
> > >
> > > Thanks for your help.
> > >
> > > Best regards,
> > > Jay Azurin
> > > Motorola NetComm Applications
> >

-- 
========================================================================
| Mark Bossard                     |                                   |
| Direct Phone: (410) 872-9267     | Atmel Corporation                 |
| Main Phone:   (410) 312-4400     | Chesapeake Design Center          |
| Fax:          (410) 312-4424     | 6740 Alexander Bell Dr, Suite 100 |
| Email:        mbossard@atmel.com | Columbia, MD 21046                |
========================================================================