Multiplication Factor (m)

The multiplication factor (m) puts m devices in parallel. m is an instance parameter and need not be an integer. All devices have the multiplication factor capability.

If you specify m in an instance statement, all currents and capacitances of that device are multiplied by m, and all resistances are divided by m. The multiplication factor, however, does not affect short-channel or narrow-gate effects in MOSFETs. For example, the following two statements might not give you the same simulation results:

m1 d g s b my_model w=10u l=1u m=10

m1 d g s b my_model w=100u l=1u m=1

You can also specify the multiplication factor on subcircuits. If a multiplication factor is specified in a subcircuit, it applies to all elements in that subcircuit. For example, if the multiplication factor of the subcircuit is 2 and the multiplication factor of an element in the subcircuit is 3, the effective multiplication factor for that element is 6.

Some devices—such as BJT, JFET, and diode—have an area factor parameter (area). The area parameter has identical effect on devices as the multiplication factor.

Spectre Circuit Simulator Components and Device Models Reference
Product Version 23.1, June 2023