Table of Contents

Capacitor, advanced

Syntax: instance

Spice format

Cxxxxxxx n+ n– value
Cxxxxxxx n+ n– expression
Cxxxxxxx n+ n– value {IC=initial-voltage}
Cxxxxxxx n+ n– model {L=length} {W=width} {TEMP=temperature} {IC=initial-voltage}

Spectre format

Cxxxxxxx n+ n– capacitor C=value
Cxxxxxxx n+ n– capacitor expression
Cxxxxxxx n+ n– capacitor C=value {IC=initial-voltage}
Cxxxxxxx n+ n– model {L=length} {W=width} {TEMP=temperature} {IC=initial-voltage}

Verilog format

capacitor #(.c(value)) 
Cxxxxxxx n+ n– value
Cxxxxxxx n+ n– expression
Cxxxxxxx n+ n– value {IC=initial-voltage}
Cxxxxxxx n+ n– model {L=length} {W=width} {TEMP=temperature} {IC=initial-voltage}
.capacitor label n+ n– expression 

Model (optional) .model mname C {args} .model mname TABLE {args}

Purpose

Capacitor, or general charge storage element.

Comments

N+ and n– are the positive and negative element nodes, respectively. Value is the capacitance in Farads.

The (optional) initial condition is the initial (time = 0) value of the capacitor voltage (in Volts). Note that the initial conditions (if any) apply only if the UIC option is specified on the transient command.

You may specify the value in any of these forms: A simple value. This is the capacitance in Farads.

An expression, as described in the behavioral modeling chapter. The expression can specify the charge as a function of voltage, or the capacitance as a function of time.

A model, as described in the behavioral modeling chapter. The table model describes a table of charge vs. voltage.

A model, which calculates the capacitance as a function of length and width, referencing a .model statement of type C. This is compatible with the Spice-3 “semiconductor capacitor”.