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Resistors
- General Form:
rname n1 n2 [value | modname]
[r=expr] [temp=temp [tc1=tcoeff1]
[tc2=tcoeff2] [l=length] [w=width]
- Examples:
rload 2 10 10k
rmod 3 7 rmodel l=10u w=1u
The nominal-temperature resistance value can be specified as a bare
number, if it is the first parameter following the node list. This
token can also be a resistor model name. The paramaters that can
follow are:
- r=expr
This can also be given as ``res=expr'' or ``resistance=expr'', where expr is an expression giving
the nominal-temperature device voltage divided by device current
(``large signal'' resistance) in ohms, possibly as a function of other
variables. This form is applicable when the first token following the
node list is not a resistance value or model name. It also applies
when a model is given, it overrides the geometric resistance value.
- temp=temp
The temp is the Celsius operating temperature of the resistor,
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. The keyword
``tc'' is an alias for ``tc1''.
- 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 resistor. This applies only when a model is given,
which will compute the resistance from geometry.
- w=width
The width of the resistor. This applies only when a model is given,
which will compute the resistance from geometry.
The n1 and n2 are the two element nodes, and value
is the resistance, for a constant value resistor. A resistor model
modname can alternatively be specified and allows the
calculation of the actual resistance value from strictly geometric
information and the specifications of the process. If value is
specified after modname, it overrides the geometric information
(if any) and defines the nominal-temperature resistance. If modname is specified, then the resistance may be calculated from the
process information in the model modname and the given length and width. In any case, the resulting value will be
adjusted for the operating temperature temp if that is
specified, using correction factors given. 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.
If the resistance can not be determined from the provided parameters,
a fatal error results. This behavior is different from traditional
Berkeley SPICE, which provides a default value of 1K.
Next: Resistor Model
Up: Passive Element Lines
Previous: Coupled (Mutual) Inductors
Contents
Index
Stephen R. Whiteley
2012-09-24