Scaling Factors (scale and scalem)

scale and scalem are options that set the scaling factors for instance and model parameters, respectively. You can specify the scaling factors in the .options statement. The following devices are affected by scale or scalem:

• Capacitors
• Diodes
• Resistors
• Physical resistors (phy_res)
• All levels of MOSFET models

These scaling factors affect capacitors, resistors, and physical resistors with specified device length (l) or width (w). scale and scalem are global options and apply to all instance and model statements for the preceding list of devices.

Parameters are scaled according to the following rules:

• Model (instance) parameters containing units of m (meters) are multiplied by scalem (scale).
• Model (instance) parameters containing units of mn are multiplied by scalemn (scalen), where n can be a positive integer or a positive real number.
• Model (instance) parameters containing units of 1/m are divided by scalem (scale).
• Model (instance) parameters containing units of 1/mn are divided by scalemn (scalen), where n can be a positive integer or a positive real number.
• Parameters that use the units cm (1/cm, cm2, ...) and μm (1/μm, μm2, ...) are not scaled. For example, vmax, which contains the unit m/sec, is scaled by scalem, but ucrit, which has the unit V/cm, is not scaled. Similarly, nsub, which has the unit 1/cm3, is not scaled by scalem.
• Parameters with other units are not scaled.

Related Topics

Multiplication Factor (m)

imelt and imax

SPICE Compatibility Flag (compatible)

Parameters Common to All Devices