SPICE modeling of a BJT from Datasheet

BJT bipolar transistors require a certain number of parameters to get a good model.The syntax for this model is:

.model ModelNameNPN (par1=a par2=b………parn=x)

for PNP case:

.model ModelNamePNP (par1=a par2=b………parn=x)

where par1 par2…….parn are the parameters that allow to model equations of the BJT.

The main parameters for a reasonable modeling of the behavior of the component are summarized in the following table:

ParametersDescriptionUnitsDefault Value
ISTransport saturation currentA1e-16
XTIIS temperature effect exponentno unit dimension3.0
EGBandgap voltage (barrier height)eV1.11
VAFForward Early voltageVInfinite
BFIdeal maximum forward betano unit dimension100
ISEBase-emitter leakage saturation currentA0
NEBase-emitter leakage emission coefficientno unit dimension1.5
IKFCorner for forward-beta high-current roll-offAInfinite
NKHigh-current roll-off coefficientno unit dimension0.5
XTBForward and reverse beta temperature coefficientno unit dimension0
BRIdeal maximum reverse betano unit dimension1.0
ISCBase-collector leakage saturation currentA0
NCBase-collector leakage emission coefficientno unit dimension2.0
IKRCorner for reverse-beta high-current roll-offAInfinite
RCCollector ohmic resistanceOhm0
CJCBase-collector zero-bias p-n capacitanceF0
MJCBase-collector p-n grading factorno unit dimension0.33
FCForward-bias depletion capacitor coefficientno unit dimension0.5
CJEBase-emitter zero-bias p-n capacitanceF0
MJEBase-emitter p-n grading factorno unit dimension0.33
VJEBase-emitter built-in potentialV0.75
TRIdeal reverse transit timesec1e-8
TFIdeal forward transit timesec0
ITFTransit time dependency on IcA0
XTFTransit time bias dependence coefficientno unit dimension0
VTFTransit time dependency on VbcVInfinite
RBZero-bias (maximum) base resistanceOhm0