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IBIS Model Usage
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Contents:
1) General Suggestions
2) Configuring the PIN parameter
3) Selecting the required package
4) PCI related
5) Calculating the max/min source/sink current from the IBIS models
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1) General Suggestions

It is always good to open the IBIS model in a text editor and look for any
model specific intructions that might be included. Since these appear as
inline comments in the model, simulators will ignore them by default.
2) Configuring the PIN parameter (Not applicable to ProASICplus)

Each Actel IBIS model contains a pin named ALLIO. This pin can serve as a
signal pin during board level simulations. Simply replicate the pin as
many times as needed to suit your design.
3) Selecting the required package (for all models)

The IBIS model(s) contain package parasitics under R_pkg, L_pkg, C_pkg.
The model(s) usually have information for more than one package. All package
data except for one will be commented out by default. The pipe () symbol in
the first column is the comment character. Please uncomment the appropriate
package before starting the simulation.
example:

R_pkg 0.800 NA NA  FG896
L_pkg 6.19nH NA NA  FG896
C_pkg 3.59pF NA NA  FG896

R_pkg 0.711 NA NA  FG676
L_pkg 5.75nH NA NA  FG676
C_pkg 3.07pF NA NA  FG676

R_pkg 0.566 NA NA  BG456
L_pkg 7.49nH NA NA  BG456
C_pkg 2.18pF NA NA  BG456

4) PCI related (Only ProASICplus PCI models)

According to the PCI spec the Vref and Vmeas parameters are different depending
on the edge under consideration. So for the PCI models Vref and Vmeas
parameters are commented out and are given seperatly for both edges. Please
uncomment the values corresponding to the required edge.
5) Calculating the max/min source/sink current from the IBIS models

The brief description below is the procedure to get the MAX source/sink current
from the IBIS model. These are not guaranteed values as results may vary slightly
from device to device. For detailed information about background and usage of
IBIS models, please refer to the application note:
http://www.actel.com/appnotes/Ibis_AN.pdf.
Positive current is defined as current flowing into the device.
The voltage in IBIS model tables are derived from the equations below:
Vtable = VCC  Voutput (in Pullup section for source current)
Vtable = Voutput (in Pulldown section for sink current)
To get the MAX source/sink current at the correct operating voltage, you need to
consider the Min/Max value of VOH/VOL from the DC Specification listed in your
devices corresponding datasheet:
Vtable = VCC  VOH(Min) (for MAX source current)
Vtable = VOL(Max) (for MAX sink current)
For example, the DC Spec in the SXA datasheet shows that VOH(Min) is
2.4V at 3.3V LVTTL, so the corresponding WORST case MAX source current, I(min),
is 35mA as shown below at Vtable = 3.3V – 2.4V = 0.9V. The BEST case MAX source
current corresponds to I(max) which is equal to 50.9mA at Vtable = 0.9
[Temp Range] 25.0000 0.1250k 54.0000
[Voltage Range]3.3000V 3.0000V 3.6000V
[Pullup]
 voltage I(typ) I(min) I(max)
0.7000 34.9100mA 28.4922mA 41.0565mA
0.8000 39.1200mA 31.8780mA 46.0863mA
0.9000 43.1300mA 35.0757mA 50.9141mA <
1.0000 46.9400mA 38.0952mA 55.5197mA
1.1000 50.5500mA 40.9365mA 59.9031mA
Actel Corporation
May 29, 2002