APPLICATION NOTE
2
A better IC model can improve PSpice simulation accuracies, but other components, such as, passive
components, can influence simulation accuracy as much as IC models. This application note will cover
various examples to describe the effects of frequency and temperature on the behavior of selected
common passive components.
Frequency Effects
This section covers the effects of frequency on the behavior of the following selected models:
Resistor Models
Ceramic Capacitor Models
Other Common Components
o Conductors
o Inductors
Resistor Models
A resistor that appears to work in straightforward manner can change its behavior with respect to the
Operating frequency in a DC circuit. Depending upon its value and frequency of an operation, a resistor
can behave in a resistive, capacitive, or inductive manner.
Figure 1: Resistor Model Circuit
In Figure 1, you can see that three major elements are associated with a standard 0.25-watt carbon or
metal film resistor. With the first being the resistor itself, second and third are the two major parasitic
elements that are included with every resistor. One is a parasitic capacitor formed across the resistor; this
capacitor reduces the resistor's impedance at high frequency. Other is a parasitic lead inductance; this
inductance increases the impedance as frequency increases.
