Capacitors

- General Form:
`c`*name**n*+*n*- [*value*|*modname*] [*options*] [c=*expr*|`poly`*c0*[*c1*...]]

*Options*: [m=*mult*] [ic=*val*] [temp=*temp*[tc1=*tcoeff1*] [tc2=*tcoeff2*] [l=*length*] [w=*width*]

- Examples:
`cload 2 10 10p`

cmod 3 7 cmodel l=10u w=1u

The *n*`+` and *n*`-` are the positive and
negative element nodes, respectively, and *value* is the
capacitance for a constant valued capacitor. Alternatively, a
capacitor model *modname* can be specified which allows for the
calculation of the actual capacitance value from strictly geometric
information and the specifications of the process. If *value*
is specified, it defines the capacitance. If *modname* is
specified, then the capacitance is calculated from the process
information in the model *modname* and the given *length* and
*width*. If *value* is not specified, then *modname*
and *length* must be specified. If *width* is not
specified, then it will be taken from the default width given in the
model. Either *value* or *modname*, *length*, and
*width* may be specified, but not both sets.

The parameters accepted by the capacitor are:

`m=`*mult*

This is the parallel multiplier which is the number of devices effectively in parallel. The given capacitance is multiplied by this value. It overrides any ``m`' multiplier found in the inductor model.`ic=`*val*

The optional initial condition*val*is the initial (time zero) voltage across the capacitor. The initial condition (if any) applies only when the`uic`option is specified in transient analysis.`temp=`*temp*

The*temp*is the Celsius operating temperature of the capacitor, for use by the temperature coefficient parameters.`tc1=`*tcoeff1*

The first-order temperature coefficient. This will override the first-order coefficient found in a model, if given.`tc2=`*tcoeff2*

The second-order temperature coefficient. This will override the second-order coefficient found in a model, if given.`l=`*length*

The length of the capacitor. This applies only when a model is given, which will compute the capacitance from geometry.`w=`*width*

The width of the capacitor. This applies only when a model is given, which will compute the capacitance from geometry.`c=`*expr*

This can also be given as ```cap=`*expr*'', or ```capacitance=`*expr*'', where*expr*is an expression yielding the capacitance in farads. This is the partial derivative of charge with respect to voltage, possibly as a function of other circuit variables. This form is applicable when the first token following the node list is not a capacitance value or model name. It also applies when a model is given, it overrides the geometric capacitance value.This is the default keyword, so actually the parameter name and equals sign are optional, a bare expression is acceptable.

`poly`*c0*[*c1*...]

This form allows specification of a polynomial capacitance, which will take the formCapacitance =

where*c*0 +*c*1^{ . }*v*+*c*2^{ . }*v*^{2}...*v*is the voltage difference between the positive and negative element nodes. There is no built-in limit to the number of terms.