NLCAPA is a replacement for NLCAP. It also provides all of the functionality found in Spectre's capacitor, or HSPICE's C device.

Name | Description | Unit Type | Default |
---|---|---|---|

ID | Element ID | Text | C1 |

*L | Capacitor length | Length | 0 |

*W | Capacitor width | Length | 0 |

*AREA | Capacitor area | ||

*PERIM | Capacitor perimeter | ||

MULT | Multiplicity factor | 1 | |

*TC1 | Linear temperature coefficient of capacitance | 0 | |

*TC2 | Quadratic temperature coefficient of capacitance | 0 | |

*TNOM | Parameter extraction temperature | Temperature | 26.85DegC |

*TEMP | Device temperature | Temperature | _TEMP |

C | Capacitance | Capacitance | |

*ETCH | Width narrowing due to etching per side | Length | 0 |

*COEFFS | Vector of polynomial coefficients | ||

*CJ | Bottom capacitance density | ||

*CJSW | Sidewall capacitance density | ||

*THICK | Dielectric thickness | ||

*DI | Relative dielectric constant |

The letter pair pn identifies the only NL branch of this model. Consequently, Vpn and Ipn identify voltage and current of this branch, respectively.

Parameter | Description |
---|---|

cap (Capacitance) | Element capacitance |

Several differences are noticed when NLCAPA is compared with its predecessor NLCAP: polynomial coefficients are entered as a vector, COEFF={C0,C1,...}, instead of as individual parameters; there is temperature compensation support, in terms of parameters TC1 and TC2; and; the capacitance may be entered directly, or, calculated it from the physical length and width of the capacitor. In either case, the capacitance may be a function of temperature, or, applied voltage.

The capacitance is given by

And the corresponding charge by

This element does not have an assigned layout cell. You can assign artwork cells to any element. See “Assigning Artwork Cells to Layout of Schematic Elements” for details.

**NOTE:** NLCAPA is implemented as a nonlinear device in
harmonic balance simulations, independently of whether the polynomial truly describes a
nonlinear device. As a result, from a performance standpoint, it is advisable to limit
the use of this element to those cases where the desired functionality cannot be
implemented by a simpler linear element, such as CAP.