Re: True or False?

All,

I believe the more appropriate solution is to model the
device using an ebd model. In this way a differential
receiver can be place on the pass-thru between the
input and output pins of the device.

Ebd models work quite well for complex package
situations, such as this one.

Regards,

Scott

Chris Rokusek wrote:

> Arpad,
>
> Since you must have the [Series Map] to connect IN to OUT and therefore
> must have terminators on those pins to stay "legal" for the time being,
> I urge for you to leave out the [Diff Pin] relationship and rely on
> another device within the board to associate the nets since you can't
> legally put an actual sensing receiver at the series pin locations
> anyway.
>
> As a temporary solution, this method would result in the proper
> connectivity for our customers...any other vendors care to comment?
>
> If you want to leave it in that is your choice as I must surrender that
> your model may actually be legal--perhaps due to an oversight in the
> [Diff Pin] specification (noticed I used the word "may"!!). We will
> instruct our customers to delete the [Diff Pin] lines until we are able
> to support it with a patch (yuck!).
>
> Viewlogic will endorse a proposed BIRD allowing other types of models on
> the series pin nodes.
>
> Chris
>
> P.S. I will be out of the office all next week so am defenseless to
> your reply :) !!
>
> Muranyi, Arpad wrote:
> >
> > Chris,
> >
> > I don't know what it feels like to be an attorney, because I have never been
> >
> > one. I wonder about the same question...
> >
> > Regarding A) The device has a differential input, so I DO HAVE TO use the
> > [Diff Pin] keyword. The die has a direct connection between
> > the
> > pads which do the loopback, so I must have a way to describe
> > the
> > series properties of those connections. The only model type
> > that
> > is allowed in the IBIS spec with the series models is the
> > "non-sensing" Terminator model type. Do you have a suggestion
> > for
> > how to model this other than the way I did it? I am willing to
> > make changes if it makes sense...
> >
> > Regarding B) I have to make a model now, since the customer wants to use it
> > immediately. Even though I would prefer this, I can't wait for
> > a
> > new IBIS spec version.
> >
> > I don't see why my model is "debatebly" legal because nothing I did in it is
> >
> > illegal according to the spec. The model makes sense if you think about
> > what it
> > describes and not about what the comments in the spec say regarding what the
> >
> > Terminator models could be used for.
> >
> > So we have a choice of fixing the spec, make legal (but "senseless"?
> > models), or
> > not have any models. Which one would you choose when the customer wants to
> > simulate and is pounding on the door for models?
> >
> > Remember, this is an existing device and we should both be interested in
> > finding
> > a way to model it.
> >
> > Arpad
> > ============================================================================

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___________________________
Scott McMorrow
Principal Engineer
SiQual
mailto:scottmc@siqual.com
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