Re: Question on the Sweep range

From: Arpad Muranyi <Arpad_Muranyi@ccm.fm.intel.com>
Date: Mon Jun 27 1994 - 11:46:05 PDT

Scott,

Since there is only one voltage column for the three cases of current columns in
the IBIS models, in my mind this rule references the typical voltage range.
Therefore my models all have a -5V to +10V range regardless whether the columns
are typ., min., or max.

This is actually not a very important issue anyway. The lab measurements can
not go that far in most cases. The main reason we added this rule was to make
sure that all simulators cover the widest possible range correctly, because they
do not all extrapolate the same way beyond the last data point. For example, if
your last data point is at -1V, one tool might continue with the last slope,
another might continue horizontally, and another vertically. If you had a -2V
undershoot, you would see very different results.

Arpad Muranyi
Intel Corporation

After reading all the ibis specs that are available to me, I can
not find this
answer anywhere.

For the voltage ranges, version 1.1 and 2.0 specs state:

2) Voltage Ranges:
| Points for each curve must span the voltages listed below:
|
| Curve Low Voltage High Voltage
| ----------- ----------- ------------
| [Pulldown] GND - POWER POWER + POWER
| [Pullup] GND - POWER POWER + POWER
| [GND Clamp] GND - POWER GND + POWER
| [POWER Clamp] POWER POWER + POWER

Now the question I have is this. When you are sweeping on the non-typical
voltage, what is the range. Meaning, if you have a 5 volt power supply,
with a minimum voltage of 4.5 volts. Does you sweep for the pullup
now go from
-4.5 volts to 9 volts? or from -5 to 5 as before?

Thanks in advance,

Scott Aron Bloom
InterConnectiX, Inc.
Received on Mon Jun 27 10:49:37 1994

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