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Piecewise Linear MOSFET



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 .

PWLMOSFET Internal Model


The capacitances are calculated as follows:

C_{GS} = C_{ISS} - C_{RSS}
C_{DS} = C_{OSS} - C_{RSS}
C_{GD} = C_{RSS}

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 or file an issue on Github. A list of known issues can be found here.


Electrical > Semiconductors


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


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
Crss Reverse Transfer Capacitance
Vsd_Is_BodyDiodeMatrix Source Drain current vs Source-Drain Voltage (Body Diode)