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