Exponential waveform |

Any independent source can be assigned a time-dependent value for transient analysis. The general form of exponential waveform is:

EXP ( <V1> <V2> [TDI [TAU1 [TD2 [TAU2]]]] ) |

You must specify a value for the parameters V1 and V2. the remaining parameters, if not specified, assume a default value.

Parameter | Description | Units | Default |

V1 | Initial amplitude of the output with respect to the negative terminal (usually ground). | V o A | |

V2 | Pulsed value. Maximum amplitude of the output swing. | V o A | |

TD1 | Rise delay time. The point in time, from t0, when the output begins to rise. This provides a phase shift of the output by delaying the start of the exponential waveform. | s | 0 |

TAU1 | Rise time constant. | s | TSTEP |

TD2 | Fall delay time. Fall delay time. The point in time, from t0, when the output begins to fall. | s | TD1+TSTEP |

TAU2 | Fall time constant. | s | TSTEP |

TSTEP is the printing increment and TSTOP is the final time (see the .TRAN control line for explanation).

The waveform value generated by the EXP option is as follows:

Time | Value |

0 to TD1 | V1 |

TD1 to TD2 | V1 + (V2-V1)*(1-e^{-(t-TD1)/TAU1}) |

> TD2 | V1 + (V2-V1)*(-e^{-(t-TD1)/TAU1})+(V1-V2)*(1-e^{-(t-TD2)/TAU2}) |

`VIN 3 0 EXP(-4 -1 2NS 30NS 60NS 40NS)`