An enhanced SPICE MOSFET model suitable for analog applications

A MOSFET model optimized for analog circuit simulation is presented and shown to agree with measured device characteristics, especially device output conductance and transconductance, over a wide range of operation. The widely used SPICE Level 3 (MOS3) model equations were utilized as a starting point in the model development process. The enhanced model (NMOD) exhibits smooth and continuous transitions in the weak to strong inversion region, and in the region between linear and saturation modes of device operation. These smooth transitions improve both the model´s current and conductance prediction accuracy, as well as its convergence properties when used in circuit simulation. This is made possible because a single current equation is utilized for all regions of device operation. The NMOD model accurately characterizes devices over a wide range of geometries, achieving, for example, 1.3% and 4.2% average errors between measured and model I_DS and gds characteristics, respectively, for a 20/1.3-μm p-channel device over a 5-V bias range