eldo_user

Monte Carlo Analysis
Parameter Naming Conventions
Macro PP(.)
In the following netlist, a new parameter GLOBVAR is introduced, and the instance parameter,
W, of each resistor is associated to the GLOBVAR variable:
.PARAM VAR=AUNIF(3U,0.1U)
.PARAM GLOBVAR=VAR
.PARAM BIAS=1M
I1 0 1 BIAS
I2 0 2 BIAS
R1 1 0 RESISTOR W=GLOBVAR L=VAR
R2 2 0 RESISTOR W=GLOBVAR L=VAR
.MODEL RESISTOR R LEVEL=3 W=3U L=3U RSH=100
The GLOBVAR parameter will have implicit LOT variations. Multiple references to
GLOBVAR do not create multiple random variables. The parameter variations are defined
globally; this is an artifact of the syntax that enables circuit parameters to be specified with
global variations.
For Eldo, the GLOBVAR parameter does not inherit the DEV variations of the VAR parameter,
and only one random variable will be created in the Monte Carlo sampling. This should be
avoided as much as possible in the netlist, and instead explicit specifications with the DEV/LOT
keywords should be used.
The random variable associated to this parameter GLOBVAR is named with the macro PP(.)
according to this syntax:
PP(parameter1_name, parameter2_name)
The random variable that affects the parameter parameter2_name such that its distribution is
specified in the definition of the parameter parameter1_name.
Example of Macro PP(.) and PE(.) Usage
Consider the statements:
.PARAM VAR=AUNIF(3U,0.1U)
.PARAM GLOBVAR=VAR
.PARAM LOCVAR=AUNIF(0U,0.02U)
.PARAM BIAS=1M
I1 0 1 BIAS
I2 0 2 BIAS
R1 1 0 RESISTOR W=’GLOBVAR+LOCVAR’ L=VAR
R2 2 0 RESISTOR W=’GLOBVAR+LOCVAR’ L=VAR
.MODEL RESISTOR R LEVEL=3 W=3U L=3U RSH=100
538
Eldo® User's Manual, 15.3