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:

Parameters | Description | Units | Default Value |
---|---|---|---|

IS | Transport saturation current | A | 1e-16 |

XTI | IS temperature effect exponent | no unit dimension | 3.0 |

EG | Bandgap voltage (barrier height) | eV | 1.11 |

VAF | Forward Early voltage | V | Infinite |

BF | Ideal maximum forward beta | no unit dimension | 100 |

ISE | Base-emitter leakage saturation current | A | 0 |

NE | Base-emitter leakage emission coefficient | no unit dimension | 1.5 |

IKF | Corner for forward-beta high-current roll-off | A | Infinite |

NK | High-current roll-off coefficient | no unit dimension | 0.5 |

XTB | Forward and reverse beta temperature coefficient | no unit dimension | 0 |

BR | Ideal maximum reverse beta | no unit dimension | 1.0 |

ISC | Base-collector leakage saturation current | A | 0 |

NC | Base-collector leakage emission coefficient | no unit dimension | 2.0 |

IKR | Corner for reverse-beta high-current roll-off | A | Infinite |

RC | Collector ohmic resistance | Ohm | 0 |

CJC | Base-collector zero-bias p-n capacitance | F | 0 |

MJC | Base-collector p-n grading factor | no unit dimension | 0.33 |

VJC | V | 0.75 | |

FC | Forward-bias depletion capacitor coefficient | no unit dimension | 0.5 |

CJE | Base-emitter zero-bias p-n capacitance | F | 0 |

MJE | Base-emitter p-n grading factor | no unit dimension | 0.33 |

VJE | Base-emitter built-in potential | V | 0.75 |

TR | Ideal reverse transit time | sec | 1e-8 |

TF | Ideal forward transit time | sec | 0 |

ITF | Transit time dependency on Ic | A | 0 |

XTF | Transit time bias dependence coefficient | no unit dimension | 0 |

VTF | Transit time dependency on Vbc | V | Infinite |

RB | Zero-bias (maximum) base resistance | Ohm | 0 |