RE: [IBIS] Filling C_comp value in IBIS file

If all else fails, read the spec...
 
|=======================================================================
======
|
|                                 Section 9
|
|     N O T E S    O N    D A T A    D E R I V A T I O N    M E T H O D
|
|=======================================================================
======
...
...
...
| The "min" and "max" columns for all remaining keywords and
subparameters
| will contain the smallest and largest magnitude values.  This applies
to the
| [Model] subparameter C_comp as well even if the correlation to the
voltage,
| temperature, and process variations are known because information
about such
| correlation is not available in all cases. 

 
Arpad
|=======================================================================
======


________________________________

From: owner-ibis@eda.org [mailto:owner-ibis@eda.org] On Behalf Of
Ummalaneni, Venu Babu (Venu)
Sent: Wednesday, April 27, 2005 4:32 AM
To: ibis-users; ibis
Subject: [IBIS] Filling C_comp value in IBIS file



Hi All, 

I hope that for filling the typ, min and max column data under V-I and
V-t tables, PVT conditions are defined for each column.

[Approach 1] 
But for filling the data under the [C_comp] keyword these PVT conditions
are not defined. We are taking worst case fast process corner,  maximum
voltage and minimum temperature   values for filling [C_comp] min
column. And reverse for max column.

By following  above procedure for some buffers we are not getting C_comp
values as per desirable sequence C_Comp(min) < C_comp(typ) <
C_Comp(max).

And hence we are getting warning message from the golden parser. 

Recently, I read following para from Cook book: 

[Approach 2] 
The C_comp parameter specifies the buffers input, output or I/O
capacitance and can have a typical, minimum and maximum value.  Note
that when constructing the IBIS file the numerically largest value of
C_comp is listed as the 'max' value while the numerically smallest value
of C_comp is listed as the 'min' value.  C_Comp min and max values do
not necessarily correlate with the min and max conditions under which
the I/V and switching data was gathered.

Which one need to follow? Approach 1 or Approach 2? 

Thanks in advance. 

Best Regards, 
Venu. 





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