A table look-up model using a 3-D isoparametric shape function with improved convergency

A table look-up model for MOSFETs has been implemented into SPICE2G.6 to compute I/sub ds/ and its first-order derivatives using a three-dimensional linear isoparametric shape function. This method accurately calculates continuous and monotonic I/sub ds/ and its continuous first-order derivatives with a relatively small number of data points. As a consequence, this table look-up model converges more rapidly, compared to the analytic model of SPICE2G.6. The total number of Newton-Raphson iterations is on the average 10% less than that of SPICE2G.6 simulation. >