ecl models in ibis

IBIS Gurus, Experst, Inventors, and Developers:

Can anybody clarify the following ECL model related issues in IBIS.
Below is an excerpt from IBIS file (downloaded from internet).
I have 2 questions regasrding these data.

1) Why current in PU/PD tables is always negative? Why
   the buffer "ECL_OBUF3_5" always source current and never sink current?
   Is this something "ECL_OBUF3_5" model specific or it is a typical case for
   Output_ECL buffer?

2) regarding:

   [Voltage Range] 0.0 0.0 0.0
   [Pulldown Reference] 0.0 0.0 0.0
   [Power Clamp Reference] 0.0 0.0 0.0
   [GND Clamp Reference] -3.3 -3.0 -3.8

   Why [Pulldown Reference] = 0, why not to use [Pulldown Reference] = -3.3V ?
   THis question is more about conventions used.
   It is clear what voltages are applied. Why not to use notations:

   [Voltage Range] 0.0 0.0 0.0
   [Pullup Reference] 0.0 0.0 0.0 (*)
   [Pulldown Reference] -3.3 -3.0 -3.8
   [Power Clamp Reference] 0.0 0.0 0.0 (*)
   [GND Clamp Reference] -3.3 -3.0 -3.8

   (*) indicate optional parameter (no need to include it, but no harm if it is
       given)

Thank you

Nik

nikolai@avanticorp.com

[IBIS ver] 2.1
[File name] mc_lvecl.ibs
[File Rev] 1.2
[Date] 4/28/98
[Source] Motorola spice models
[Notes] This ibis package is made for Motorola ECLinPS and ECLinPS Lite
               families, and is particularly for the Low Voltage family. It
               includes

[Model] ECL_OBUF3_5
Model_type Output_ECL
Polarity Non-Inverting
Vmeas = -1.3
Rref = 50.0
Vref = -2.0
|
|Variable typ min max
C_comp 2.9p 2.0p 6.0p
|
|Variable typ min max
[Temperature Range] 27 0 85
|
|Variable typ min max
[Voltage Range] 0.0 0.0 0.0
[Pulldown Reference] 0.0 0.0 0.0
[Power Clamp Reference] 0.0 0.0 0.0
[GND Clamp Reference] -3.3 -3.0 -3.8
|
[Pulldown]
|Volts I(typ) I(min) I(max)
+3.00 -2.290e-01 -1.623e-01 -2.832e-01
+2.90 -2.152e-01 -1.523e-01 -2.603e-01
+2.80 -2.010e-01 -1.419e-01 -2.422e-01
+2.70 -1.862e-01 -1.312e-01 -2.240e-01
+2.60 -1.707e-01 -1.201e-01 -2.050e-01
+2.50 -1.544e-01 -1.085e-01 -1.850e-01
+2.40 -1.372e-01 -9.633e-02 -1.637e-01
+2.30 -1.189e-01 -8.357e-02 -1.410e-01
+2.20 -9.939e-02 -7.012e-02 -1.166e-01
+2.10 -7.841e-02 -5.592e-02 -9.036e-02
+2.00 -5.586e-02 -4.094e-02 -6.207e-02
+1.90 -3.210e-02 -2.537e-02 -3.272e-02
+1.80 -1.011e-02 -1.036e-02 -8.403e-03
+1.70 -6.249e-04 -1.060e-03 -5.795e-04
+1.60 -1.429e-05 -1.917e-05 -2.407e-05
+1.50 +0.000e+00 +0.000e+00 +0.000e+00
+1.00 +0.000e+00 +0.000e+00 +0.000e+00
+0.50 +0.000e+00 +0.000e+00 +0.000e+00
+0.00 +0.000e+00 +0.000e+00 +0.000e+00
|
|
[Pullup]
|Volts I(typ) I(min) I(max)
+3.00 -2.528e-01 -1.876e-01 -3.089e-01
+2.90 -2.436e-01 -1.790e-01 -2.977e-01
+2.80 -2.346e-01 -1.709e-01 -2.869e-01
+2.70 -2.258e-01 -1.639e-01 -2.761e-01
+2.60 -2.169e-01 -1.571e-01 -2.653e-01
+2.50 -2.081e-01 -1.503e-01 -2.545e-01
+2.40 -1.992e-01 -1.433e-01 -2.437e-01
+2.30 -1.902e-01 -1.361e-01 -2.328e-01
+2.20 -1.812e-01 -1.288e-01 -2.219e-01
+2.10 -1.721e-01 -1.212e-01 -2.110e-01
+2.00 -1.630e-01 -1.135e-01 -2.000e-01
+1.90 -1.536e-01 -1.055e-01 -1.889e-01
+1.80 -1.440e-01 -9.734e-02 -1.777e-01
+1.70 -1.339e-01 -8.885e-02 -1.664e-01
+1.60 -1.229e-01 -8.005e-02 -1.548e-01
+1.50 -1.106e-01 -7.090e-02 -1.426e-01
+1.40 -9.719e-02 -6.136e-02 -1.282e-01
+1.30 -8.285e-02 -5.139e-02 -1.079e-01
+1.20 -6.708e-02 -4.094e-02 -8.326e-02
+1.10 -4.788e-02 -2.997e-02 -5.614e-02
+1.00 -2.591e-02 -1.797e-02 -2.801e-02
+0.90 -6.389e-03 -5.536e-03 -6.124e-03
+0.80 -2.749e-04 -2.551e-04 -3.688e-04
+0.70 -6.068e-06 -3.933e-06 -1.513e-05
+0.60 +0.000e+00 +0.000e+00 +0.000e+00
+0.40 +0.000e+00 +0.000e+00 +0.000e+00
+0.20 +0.000e+00 +0.000e+00 +0.000e+00
+0.00 +0.000e+00 +0.000e+00 +0.000e+00
|
|
[Ramp]
|Variable typ min max
dV/dt_r 0.48/0.32n 0.46/0.34n 0.48/0.26n
dV/dt_f 0.47/0.30n 0.45/0.33n 0.49/0.26n
|
Received on Fri Nov 13 14:34:04 1998