APPLICATION NOTE
2
Introduction
This application note will illustrate the method of creating nonlinear resistors using Analog Behavioral
Modeling by creating the transfer function for a linear conductance. A conductance can be thought of as a
voltage-controlled current source: the current between its nodes is a constant, times the voltage across
those same nodes. For example:
GCOND A B VALUE = {V(A,B)*0.1}
Where A and B represent the positive and negative terminal nodes of the voltage source V2.
This represents a linear conductance with a value of 1 milli-ohm (that is, a 1m ohm resistor). The
controlling nodes are the same as the output nodes.
Figure 1: Linear Conductance
For a nonlinear conductance the appropriate nonlinear function is used, but the device still has the same
controlling and output nodes:
GSQ A B VALUE = {V(A,B)*V(A,B)*V(A,B)*1}
Where A and B represent the positive and negative terminal nodes of the voltage source V13.
GSQ has a small-signal conductance of 3×1×V(A,B)
2
. (The small-signal conductance is the derivative
of the transfer function.)
Figure 2: Quadratic Conductance
