# Piecewise Linear MOSFET ## Description

This MOSFET model is developped with two key objectives:

1. Accuracy and Computational Efficiency: The model accurately simulates both switching and static behaviors of MOSFETs and is optimized for fast simulation.
2. Robustness and Characterization: It is designed to be robust and can be easily characterized using standard datasheet.

This MOSFET model incorporates:

• Three nonlinear capacitances $C_{GD}$, $C_{GS}$, and $C_{DS}$ characterized by Capacitance-$V_{DS}$ matrices, modeling $C_{ISS}$, $C_{OSS}$, and $C_{RRS}$ respectively.
• A PWL Diode representing the MOSFET body diode, characterized by a Voltage-Current data matrix.
• An internal piecewise linear MOSFET model using 3D Triangular meshing for output and transfer characteristics (details below).
• An internal gate resistance $R_G$. ### Capacitances

The capacitances are calculated as follows:

Capacitance Consistency

It is recommended that all three capacitances share the same $V_{DS}$ values. If not, interpolation is used to calculate missing $V_{DS}$ values.

Capacitance Options

Alternatively, a single capacitance value can be used to model a $V_{DS}$-independent capacitance.

### Body Diode

To accurately model the diode's off state, include at least one data point with a negative voltage in the characteristics matrix. In most cases, modeling avalanche breakdown is unnecessary.

### MOSFET Equations

The internal MOSFET model employs the following drain current equations: Optimization techniques are employed to derive $V_{th}$, $\lambda$, and $K$ from the output and transfer characteristics data. DIRECT (DIviding RECTangles) algorithm is used for this optimization, as described in:

• D. R. Jones, C. D. Pertunen, and B. E. Stuckmann, "Lipschitzian optimization without the lipschitz constant," J. Optimization Theory and Applications, vol. 79, p. 157 (1993).

### Beta Status

The Piecewise Linear MOSFET model is currently in Beta. It is not advised for production use. For issues, contact support@simba.io or file an issue on Github. A list of known issues can be found here.

## Library

Electrical > Semiconductors

## Pins

Name Description
Drain Drain
Source Source
Gate Gate (Control Input)

## Parameters

Name Description
Rg Gate Internal Resistance value, in Ohm
VgsIdMatrix Transfer Characteristic
VgsIdMatrix_Vds Transfer Characteristics Vds
VdsIdMatrix Output Characteristics
VdsIdMatrix_Vgs Output Characteristics Vgs
Ciss Input Capacitance, in F
Coss Output Capacitance