The Cadence® NLRESA element is a replacement for NLRES. It also provides most of the functionality found in Spectre's resistor and phy_res elements, and in HSPICE's Wire RC model. This device has three different modes of operation: wire, physical resistor, and nonlinear resistor. In the wire mode of operation, NLRESA supports most of the functionality available in both Spectre's resistor and in HSPICE's Wire RC model. In the phy_res mode of operation, NLRESA implements Spectre's phy_res element. In the nonlinear resistor mode (default), NLRESA behaves very much as its predecessor NLRES. The topology underlying each mode of operation is reflected by the device symbol.

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

ID | Element ID | Text | R1 |

TYPE | Device type | 2 | |

SUBTYPE | Substrate type | 0 | |

*R | Resistance | Resistance | |

*MULT | Multiplicity factor | 1 | |

*NFLAG | Noise flag | On | |

*L | Resistor length | Length | |

*W | Resistor width | Length | |

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

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

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

*TEMP | Device temperature | Temperature | _TEMP |

*C | Capacitance | Capacitance | |

*TC1C | Linear temperature coefficient of capacitance | 0 | |

*TC2C | Quadratic temperature coefficient of capacitance | 0 | |

*RSH | Sheet resistance | ||

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

*ETCHL | Length narrowing due to etching per side | Length | 0 |

*ETCHC | Width narrowing due to etching per side for capacitances | Length | |

*ETCHLC | Length narrowing due to etching per side for capacitances | Length | |

*COEFFS | Vector of polynomial coefficients | ||

*NONLINFORM | Form of the nonlinear resistance | 0 | |

*CJ | Bottom capacitance | ||

*CJSW | Sidewall capacitance | ||

*FC | Junction bottom capacitor forward-bias threshold | 0.5 | |

*FCSW | Junction sidewall capacitor forward-bias threshold | 0.5 | |

*MJ | Junction bottom grading coefficient | 0.5 | |

*MJSW | Junction sidewall grading coefficient | 0.33e-13 | |

*PB | Junction bottom built-in potential | 0.8 | |

*PBSW | Junction sidewall built-in potential | 0.8 | |

*THICK | Dielectric thickness | ||

*DI | Relative dielectric constant | ||

*IS | Saturation current | Current | |

*JS | Saturation current density | ||

*N | Emission coefficient | 1 | |

*CRATIO | Capacitance ratio | ||

*KF | Flicker (1/f) noise coefficient | 0 | |

*AF | Flicker (1/f) noise exponential term | 2 | |

*THIRD_TERMINAL | Third terminal connection | Grounded |

The following letter pairs have been used to identify the NL branches: pn, p0 and n0. Here pn, p0 and n0 correspond to the branches defined between the positive and negative terminals, positive and ground terminals, and negative and ground terminals, respectively. These names are used to identify branch related operating point information, i.e., branch voltages, currents, etc.

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

gpn (Conductance) | Main branch conductance |

gp0 (Conductance) | Positive terminal to ground conductance |

gn0 (Conductance) | Negative terminal to ground conductance |

cp0 (Capacitance) | Positive terminal to ground capacitance |

cn0 (Capacitance) | Negative terminal to ground capacitance |

The TYPE parameter allows you to choose between three different modes of operation: wire, physical resistor, and, non-linear resistor (resistor). The SUB_TYPE parameter, available in the physical resistor mode of operation only, allows you to choose the substrate type. Possible values are n, p or poly. Finally, the THIRD_TERMINAL parameter, available in the physical resistor and wire modes of operation only, controls whether the third terminal is grounded, or can be externally accessed.

In the nonlinear resistor mode (default), NLRESA behaves very much as its predecessor NLRES, but there are some differences worth mentioning: polynomial coefficients are entered as a vector, COEFF={C0, C1, C2, ...}, instead of as individual parameters; and; the non-linearity described by the coefficients can be either a resistance, or, a conductance. Also, NLRESA accounts for noise, both thermal and Flicker.

When NONLINFORM is set to conductance the resistive branch of the element has following I/V relationship:

When NONLINFORM is set to resistance, it has the following form:

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: **NLRESA 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 RES or REST.