Subject: [IBIS] s2ibis2 for windows voltage steps problem
From: Henrik G. Madsen (hgm@vitesse.com)
Date: Wed Nov 13 2002 - 04:57:50 PST
Hey
I'm using s2ibis2 for windows to generate my IBIS model.
I have used both the Win95 and NT version found at the IBIS site
http://www.eda.org/pub/ibis/s2ibis/s2ibis2_nt/
But it seems that the tool has problems with 'interpreting' the resulting .LIS files and generating the IBIS file.
Depending on the supply voltage (or maybe the number of original measurement point) it reduces the number of available measurement points in the IBIS file, leaves 'holes' in the voltage steps, or repeat specific voltage steps, while leaving others out.
Do there exist a workaround or fix for that?
I have included three examples below, where I use the pulldown curves as example. Dumps from the IBIS files can be found in the end of this mail. I have removed voltage steps of no interest in the middle to reduce size and ease location of issue.
Example 1, 3.3V buffer
The HSPICE .LIS file includes
0.1V steps from -3.3 to 6.6V (100 points in total)
s2ibis2 reduces this to 74 points (see gencpu_io_3v3 model below). It's OK, but why not keep the 100 original points
Example 2, 2.5V buffer
Same buffer as example 1, but with a 2.5V supply voltage
The HSPICE .LIS file includes
50mV steps from -2.5V to 5.0V (151 points in total)
s2ibis2 reduces this to 101 points, i.e.. above 100 point limit. (see gencpu_io_2v5 model below). The real pain is that it keeps the 50mV step but leaves holes in the steps between -2.05V and -1.00V, and again between 3.95V and 5.0V. I know that this is not the most important area, but I would prefer no holes but larger steps in the outer area.
Example 3, 1.5V buffer
The HSPICE .LIS file includes
50mV step from -1.5V to 3.0V (91 points)
s2ibis2 keeps the 91 points, but duplicates the -1.5V and 2.5V measurements 9 times, i.e.. corrupting the IBIS file between -1.5V to -1.0V and 2.5V to 3.0V. (see hstl1_out model below).
|************************************************************************
| Model gencpu_io_3v3
|************************************************************************
|
[Model] gencpu_io_3v3
Model_type I/O
Polarity Non-Inverting
Enable Active-High
Vinl = 0.80000V
Vinh = 2.00000V
Vmeas = 1.65000V
Cref = 10.00000pF
C_comp 1.080pF NA NA
|
|
[Temperature Range] 55.000 0.120k 0.0000
[Voltage Range] 3.300V 3.000V 3.600V
[Pulldown]
| voltage I(typ) I(min) I(max)
|
-3.30000 -1.00000mA 0.0000A -2.00000mA
-3.10000 -1.00000mA 0.0000A -2.00000mA
-2.90000 -1.00000mA -1.00000mA -2.00000mA
-2.70000 -1.00000mA -1.00000mA -2.00000mA
-2.50000 -2.00000mA -1.00000mA -3.00000mA
-2.30000 -2.00000mA -1.00000mA -4.00000mA
-2.10000 -2.30000mA -1.10000mA -3.80000mA
-1.90000 -2.90000mA -1.30000mA -5.90000mA
-1.70000 -3.80000mA -1.60000mA -7.20000mA
-1.50000 -4.90000mA -2.10000mA -8.80000mA
-1.00000 -12.42000mA -5.30000mA -24.53000mA
-0.90000 -17.92000mA -7.15000mA -32.89000mA
::::: 100mV step in voltages in removed point
4.30000 57.75000mA 38.34000mA 84.39000mA
4.50000 60.45000mA 41.38000mA 84.67000mA
4.70000 64.06000mA 44.77000mA 86.87000mA
4.90000 68.27000mA 48.14000mA 90.82000mA
5.10000 72.97000mA 47.25000mA 95.72000mA
5.30000 77.97000mA 41.09000mA 0.10130A
5.50000 81.89000mA 40.18000mA 0.10750A
5.70000 79.27000mA 40.93000mA 0.11410A
5.90000 76.34000mA 42.39000mA 0.12090A
6.10000 76.82000mA 44.36000mA 0.12490A
6.60000 84.91000mA 51.24000mA 0.12820A
|************************************************************************
| Model gencpu_io_2v5
|************************************************************************
|
[Model] gencpu_io_2v5
Model_type I/O
Polarity Non-Inverting
Enable Active-High
Vinl = 0.70000V
Vinh = 1.70000V
Vmeas = 1.20000V
Cref = 10.00000pF
C_comp 1.080pF NA NA
|
|
[Temperature Range] 55.000 0.120k 0.0000
[Voltage Range] 2.500V 2.300V 2.700V
[Pulldown]
| voltage I(typ) I(min) I(max)
|
-2.50000 -1.00000mA 0.0000A -2.00000mA
-2.45000 -1.00000mA 0.0000A -3.00000mA
-2.40000 -2.00000mA -1.00000mA -3.00000mA
-2.35000 -2.00000mA 0.0000A -3.00000mA
-2.30000 -1.00000mA -1.00000mA -3.00000mA
-2.25000 -1.00000mA -1.00000mA -3.00000mA
-2.20000 -2.00000mA 0.0000A -3.00000mA
-2.15000 -2.00000mA -1.00000mA -4.00000mA
-2.10000 -1.80000mA -0.80000mA -3.80000mA
-2.05000 -1.80000mA -0.90000mA -4.00000mA
-1.00000 -10.09000mA -4.10000mA -20.71000mA
-0.95000 -11.93000mA -4.70000mA -25.25000mA
-0.90000 -14.57000mA -5.57000mA -28.86000mA
:::::: 50mV step in voltages in removed points
3.90000 43.48000mA 29.54000mA 60.96000mA
3.95000 44.46000mA 30.34000mA 62.03000mA
5.00000 46.10000mA 24.02000mA 91.11000mA
|************************************************************************
| Model hstl1_out
|************************************************************************
|
[Model] hstl1_out
Model_type Output
Polarity Non-Inverting
Vmeas = 0.75000V
Cref = 10.00000pF
C_comp 0.600pF 0.550pF 0.650pF
|
|
[Temperature Range] 55.000 0.120k 0.0000
[Voltage Range] 1.500V 1.400V 1.600V
[Pulldown]
| voltage I(typ) I(min) I(max)
|
-1.50000 -0.48960A -0.47430A -0.50820A
-1.50000 -0.48960A -0.47430A -0.50820A
-1.50000 -0.48960A -0.47430A -0.50820A
-1.50000 -0.48960A -0.47430A -0.50820A
-1.50000 -0.48960A -0.47430A -0.50820A
-1.50000 -0.48960A -0.47430A -0.50820A
-1.50000 -0.48960A -0.47430A -0.50820A
-1.50000 -0.48960A -0.47430A -0.50820A
-1.50000 -0.48960A -0.47430A -0.50820A
-1.50000 -0.48960A -0.47430A -0.50820A
-1.00000 -0.15700A -0.16210A -0.15740A
-0.95000 -0.13190A -0.13650A -0.13430A
-0.90000 -0.11060A -0.11320A -0.11730A
:::::: 50mV step in voltages in removed points
2.40000 72.01000mA 68.98000mA 85.96000mA
2.45000 78.52000mA 77.69000mA 90.01000mA
2.50000 86.36000mA 88.34000mA 94.82000mA
2.50000 86.36000mA 88.34000mA 94.82000mA
2.50000 86.36000mA 88.34000mA 94.82000mA
2.50000 86.36000mA 88.34000mA 94.82000mA
2.50000 86.36000mA 88.34000mA 94.82000mA
2.50000 86.36000mA 88.34000mA 94.82000mA
2.50000 86.36000mA 88.34000mA 94.82000mA
2.50000 86.36000mA 88.34000mA 94.82000mA
2.50000 86.36000mA 88.34000mA 94.82000mA
2.50000 86.36000mA 88.34000mA 94.82000mA
3.00000 0.34700A 0.36010A 0.33770A
_____________________________________
Henrik G Madsen
Sr. HW Engineer
Vitesse Semiconductor Corporation A/S
Ethernet Products Division
Hoerkaer 16, DK-2730 Herlev, DENMARK
Direct: +45 4485 5920
Phone: +45 4485 5900, Fax: +45 4485 5901
mail: hgm@vitesse.com
web: http://www.vitesse.com
_____________________________________
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