RE: [IBIS-Users] V-t graphs look for IBIS models

Bonnie,
 
You do not need such a recommendation. The transitioning
portion of a V-t curve can take over 90% of the total
length of the V-t curve. The only thing that is a good
thing to have is that the last two points on either end
of the curve should be horizontal. I.e. the waveforms
should start and finish settled...
 
Arpad
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________________________________

From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On
Behalf Of Baker, Bonnie
Sent: Wednesday, May 26, 2010 5:40 PM
To: ibis-users@eda.org
Subject: [IBIS-Users] V-t graphs look for IBIS models

During the QC review of our IBIS models, we had a short discussion about
the basic format of the V-t graphics. There are a few things that we
know

1. The curves should not end too soon, meaning that they have not
finished settling to their final DC value.
2. The end points should be consistent with the IV curves.
3. There are more points where the slope in changing (at least 10
points during the transitions)
4. The lead time into the V-t Table is minimized

What we don't know is if there is recommended ratio between the time
that the curve is transitioning from high to low (or low to high) versus
the time that the curve is at its final DC value? For instance, I am
recommending the approximate relationship of 1/3 to the time in
transition and 2/3 of the time at a final stabilized DC value for the
worst case curve (between the rising and falling curves).

Any thoughts?

Best Regards,

Bonnie Baker

Sr. Applications Engineer

Texas Instruments, Tucson

5411 E. Williams

Tucson, Arizona 85711

(520) 750-2116 (work)

(520) 548-3111 (cell)

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