BondLib.Spice.Utilities.RBS

# .BondLib.Spice.Utilities.RBS

Spice-style base resistor model of bipolar transistors

## Information

The base resistor is the most important of the parasitic resistors of a bipolar transistor. For this reason, Spice models this resistor using a more sophisticated model with additional parameters.

    Parameters:

     RB:     Reference zero-bias base resistance (default value = 0 Ohm)

     RBM:    Reference minimum base resistance (default value = 0 Ohm)

     IRB:    Current where base resistance falls halfway to minimum value (default value = 0 Amp)

     Tnom:   Reference temperature (default value = 300.15 oK)

     TRB1:   Linear temperature variation coefficient of RB (default value = 0 Ohm/oK)

     TRB2:   Quadratic temperature variation coefficient of RB (default value = 0 Ohm/oK2)

     TRM1:   Linear temperature variation coefficient of RBM (default value = 0 Ohm/oK)

     TRM2:   Quadratic temperature variation coefficient of RBM (default value = 0 Ohm/oK2)

     Area:   Relative area occupied by resistor (default value = 1)

     Level:  Transistor modeling level (Ebers-Moll = 1; Gummel-Poon = 2) (default value = 2)

Equations:

DTemp = e2 - Tnom
RBval = RB*(1 + TRB1*DTemp + TRB2*DTemp*DTemp)/Area
RBMval = RBM*(1 + TRM1*DTemp + TRM2*DTemp*DTemp)/Area
z = if IRB > 0 then (-1 + sqrt(1 + 144*f1/(pi*pi*IRB*Area)))/(24*sqrt(f1/(IRB*Area))/(pi*pi)) else 0
tz = if IRB > 0 then tan(z) else 0
Rval = if IRB > 0 then (Rbmval + 3*(Rbval - Rbmval)*(tz-z)/(z*tz*tz)) else (Rbmval + (Rbval - Rbmval)/qb)
e1 = Rval*f1
f2 = (e1/e2)*f1

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