Analytic transient solution of general MOS circuit primitives

The exact analytic transient solution is presented for a general MOS circuit primitive. In the circuit primitive, I-V characteristics of transistors are modeled by quadratic equations and node voltages by piecewise-linear waveforms. The proposed MOS circuit primitive, of which an inverter is a special case, is shown to be more suitable for switch level and fast timing simulations than the commonly used inverter. For circuit simulation of medium-size digital circuits containing a few hundred transistors, the application of this analytic solution has resulted in two to three orders of speed improvement over the conventional circuit simulator. The speed improvement factor is expected to grow with the circuit size. It is also shown that the exact transient solution of a macromodel which models the charge sharing can be obtained in the same way