eldo_user

Monte Carlo Analysis
Parameter Naming Conventions
where and .
The model parameters DW and DLR are the differences between drawn and actual width and
length respectively. The sheet resistance is fixed to RSH = 100.
Note
This is a simplification of the effective expression where the scaling factors have been
removed. Refer to RC Wire in the Eldo Reference Manual for the full formula.
Implicit Rule
An implicit rule exists to determine whether a parameter has global or local variations. If the
parameter P is defined as a simple random variable such as:
.PARAM P=AUNIF(...)
then this variable has implicit DEV variations. It means that each reference of P in the circuit
netlist will lead to the creation of an independent random variable.
Macro PE(.)
The following example illustrates the use of the macro PE(.). There are two references to the
VAR parameter:
.PARAM VAR=AUNIF(3U,0.1U)
.PARAM BIAS=1M
I1 0 1 BIAS
I2 0 2 BIAS
R1 1 0 RESISTOR W=3U L=VAR
R2 2 0 RESISTOR W=3U L=VAR
.MODEL RESISTOR R LEVEL=3 W=3U L=3U RSH=100
Two random variables will be associated to the resistors R1 and R2. These variables will be
named PE(VAR,R1,L) and PE(VAR,R2,L).The macro PE has three arguments. The syntax is
defined as follows:
PE(parameter_name, device_name, instance_parameter)
The random variable that affects the instance parameter instance_parameter associated to the
device device_name is such that its distribution is specified in the definition of the parameter
parameter_name.
Eldo® User's Manual, 15.3 537