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Subsections
Rxxxxxxx n+ n- value
  Rxxxxxxx n+ n- expression
  Rxxxxxxx n+ n- model {L=length}
        {W=width} {TEMP=temperature} 
  .RESistor label n+ n- expression
Resistor, or general current controlled dissipative element.
N+ and n- are the positive and negative element nodes,
respectively.  Value is the resistance in Ohms.
The resistor (type R) differs from the admittance (type Y) in
that the resistor is a current controlled element, and the conductance is a
voltage controlled element, in addition to the obvious use of conductance
( ) instead of resistance.
) instead of resistance.
You may specify the value in one of three forms:
- A simple value.  This is the resistance in Ohms.
 
- An expression, as described in the behavioral modeling chapter.
  The expression can specify the voltage as a function of current, or
  the resistance as a function of time.
 
- A model, which calculates the resistance as a function of
  length and width, referencing a .model statement of type     R.  This is compatible with the Spice-3 ``semiconductor
  resistor''.
 
A model statement may be used,, with model type R or Res.
The parameters are:
- RSH = x
- Sheet resistance. (Ohms / square). (Required)
 
- CJSW = x
- Junction sidewall capacitance. (Farads /
  meter).  (Default = 0.)
 
- DEFW = x
- Default width. (meters).  (Default = 1e-6)
 
- NARROW = x
- Narrowing due to side etching. (meters).
  (Default = 0.)
 
- TC1 = x
- First order temperature coefficient.
  (Farads / degree C).  (Default = 0.)
 
- TC2 = x
- Second order temperature coefficient.
  (Farads / degree C squared).  (Default = 0.)
 
- TNOM = x
- Parameter measurement temperature.
  (degrees C.).  (Default = 27.)
 
Resistance is computed by the formula:
resistance = RSH * (L - NARROW) / (W - NARROW)
After the nominal value is calculated, it is adjusted for temperature
by the formula:
value *= (1 + TC1 * (T-T0) + TC2 * (T-T0)^2)
 
 
 
 
 
 
 
  
 Next: S: Voltage Controlled Switch
 Up: Circuit description
 Previous: Q: Bipolar Junction Transistor
     Contents 
Al Davis
2001-10-28