My colleague and I presented a paper on making behavioral models at
DesignCon98 last month. There were several other papers on the topic as
well. I think it's safe to say that collecting accurate IBIS models is
a dilemma many of us are facing today.
There are various sources of these models, and you've probably heard
from some of them already. There are companies that make models for a
living, and there are IC vendors that supply models as a service to
their customers. Most of latter are publicly available. When you get a
model, here are some things to consider:
1. Does the model pass the IBIS syntax checker? If it doesn't, then it
wasn't checked out.
2. Get a hold of the paper, "Practical Issues with IBIS Models," by Bob
Ross. You can find it at the IBIS web site,
www.eia.org/eig/ibis/ibis.htm, under "Articles."
3. How well does the model agree with the real component(s)?
4. If the model was created from a sample part, what were the
processing conditions? Typical? Gustavo, you already touched on some
of these issues. Most of us need to know the typical and the spread
around typical so we can determine operating margins. Consider
temperature and voltage as well.
5. Make sure the model creator measured capacitance as well as IV
curves and rise/fall times.
6. What kind of driver is it, and what advanced modeling features might
7. Under what loading conditions is the model valid? Validating the
model with a standard load does not cover a transmission line load!
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We are designing several boards and we are having a very difficult time
getting models directly from the vendors.
I would like to have some information of places that can
generate (create) models for me.
The kind of models that I am looking for are
SPICE, IBIS, QUAD
I would like to know from these vendor, how do they generate models,
against what? (measured), how do the measure the models, on the pin or
the die, can they provide different corners models (Strong Process, Weak
Process), what about temperature and Voltage...... etc.
Also If possible I would like to know some personal experiences from
people that have already bought models before (are them good??)
Any information will be really appreciated.
Gustavo J. Blando
Hardware Design Engineer
I'm searching for IBIS models of the following components (or similar) :
082 40/105 SOL8/P
74ACT04 55/125 SOL14/P
74HC08 40/85 SOL14/P
Do you know if I can find them and where ?
Thanks a lot
Greg Edlund, Principal Engineer
Server Product Development
Digital Equipment Corp.
129 Parker St. PKO3-1/20C
Maynard, MA 01754
(978) 493-4157 voice
(978) 493-0941 FAX