slew propagation in cdb.

questions on cdb noise library characterization

Error Message:
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Problem statement:
For library modelling we are  trying to understand the details within the CDB noise library:

-vl_iv_curve -vh_iv_curve 
 -vl_iv_curve { { 1.2 1.08 0.96 0.84 0.72 0.6 } 
{ 0.05 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 } 
{ 2.869e-05 5.417e-05 9.634e-05 0.0001282 0.0001540 0.0001764 
           0.0001962 0.0002141 0.0002297 0.0002423 0.0002523 

1) Each output pin has a series of I and V (Ids and Vds curves) tables 
for a range of Vgs voltages. By default, Vgs varies from VDD to 0.5 VDD with 10% 
increments. 
Vds varies from 5% to 100% of the supply. 
   a) In my .cdB Vgs ranges from 1.2 to 0.6 and Vds ranges from 0.05 to 1V. 
      That suggests Vdd = 1.2V, supply =1.0V. Why is supply different than Vdd? 
        How did cdB get the value of 1.0V for supply?

     b) What is the current display in the table?  

     c) Vgs and Vds is of which part of the circuit? 
 
2) -vddres/-gndres How do we arrive at the holding strength of the output? 
    These values seems to be corresponding to the iv curve table 

3) -slews (in_slew1 in_slew2..) -rise_prop_to internal_node -Rise (prop_slew1
  prop_slew2..) -fall_prop_to internal node -Fall (prop_slew1 prop_slew2 .. ) 
 
The -slews values represent the input slew transitions (0-100% of the transition
time), and -Rise/-Fall options represent the rising or falling propagated slew that
corresponds to -rise_prop_to/-fall_prop_to internal nodes.
 
How do you measure Slew at the fall_prop_to internal node and rise_prop_to
internal node ?

Solution:
1) a)  The 1st list is the Vgs values in Volts. 
       The 2nd list is the Vds values as percentages of Vgs. 
   -vl_iv_curve { { vdd 0.9Vdd 0.8Vdd 0.7Vdd 0.6Vdd 0.5Vdd }           
                   { 5% 10% 20% 30% 40% 50% .... 100% } { Ids data } 

     b)  It is the current flowing is drawn from the output node. 
     c) Vgs = input voltage that applied to the transistor reference to ground. 
         Vds = output voltage 

2) This is a starting value for the base holding strength. It is not the final value 
   used inside CeltIC. The holding strength is the resistance of the weakest path to 
   VDD & the weakest path to GND.  vddres and gndres are not computed
   from the IV curve tables, but are computed independently.

3) The slews measured are the 20-80 by default. The internal CCC is loaded only
    by the final stage CCC. In case where the internal CCC is also connected to an
    output  (could happen in the Q, Qbar kind of outputs) then we add a set of loads
    at that output to find the slew propagation for those outputs.