Netlist parameters allow flexibility in assigning device/model parameters. The general format for defining a netlist parameter is as follows:

.param my_parameter_name = expression

Identifier Description
my_parameter_name Arbitrary parameter name. It may contain numbers, letters, and underscores but no other symbols. In addition, it must not start with a number.
expression Arbitrary expression operating on numerical constants or netlist parameters. Circuit variables (node voltage and device current) are not permitted.

Additional Notes

  • Parameters are constants, and thus may not contain any circuit variables such as node voltages or branch currents.
  • Parameters take precedence over pre-defined constants. If you define a variable called pi it will be used in place of the normal built-in constant.
  • The .circuitparams command allows you to expose parameters to certain analyses, such as parameter sweep, which can control and override the parameter value. Simply specify the .circuitparams keyword and follow it with a list of names of parameters. Alternatively, you can work with circuit parameters, which are defined and managed at schematic capture level, and not the SPICE netlist directly.

Examples


.param a = 6
.param n = {0.5}
.param maxV = a+10


V1 in 0 {maxV}
D1 in 3 mydiode
.model mydiode d(n={n+0.01})