eldo_user

Controlling Statistical Parameter Value Types
Monte Carlo Analysis
Sharing Distributions
By default, the value used for statistical parameters in .EXTRACT and .DEFWAVE commands
is the nominal value. This allows easy interpretation of results mixing both LOT and DEV
variations.
To change the type of value returned by statistical parameters, specify .OPTION
OUT_MCPARAM=LOT.
Tip
See “.PARAM” in the Eldo Reference Manual.
Related Topics
Specifying Statistical Variations for Individual Model Parameters
Assigning Statistical Variations using the .MCMOD Command
Sharing Distributions
To enable different entities to share the same distribution specify the .LOTGROUP command.
Anywhere Eldo accepts LOT or DEV specification, LOTGROUP=GROUP_NAME can be
specified.
When used in Monte Carlo statistical variation, if the LOTGROUP variation is absolute, the
same random number is added to the nominal value for each parameter of the group. If the
LOTGROUP variation is relative, the same random number is multiplied by the nominal value.
The .LOTGROUP command enables a probability distribution function to be defined that will
be shared by different entities in the circuit. It may be thought of as a template where the
location value of the distribution (the mean for example) is not specified.
The .LOTGROUP only defines the family of the distribution (Uniform, Gaussian) and its range
or variance. For example, the statement:
.LOTGROUP MY_LOT_GROUP=UNIFORM/10%
defines a template of distribution UNIF(NOM_VALUE,0.1*NOM_VALUE) where
NOM_VALUE is unspecified. The NOM_VALUE parameter will be known when a statistical
parameter is associated to the LOTGROUP distribution. For example, you could have:
.PARAM P=1.0 LOTGROUP=MY_LOT_GROUP
and the statistical parameter P will be randomly chosen in the interval [0.9, 1.1].
Tip
See “.LOTGROUP” in the Eldo Reference Manual.
Eldo® User's Manual, 15.3 429