Modeling Operational Amplifiers for Computer-Aided Circuit Analysis

A three-part model of the differential input, singleended output operational amplifier is developed for use with ECAP dc, ac, and transient circuit analysis programs, respectively. The values of the model components are easily obtainable from information provided on manufacturers' data sheets. Amplifier parameters included in the model are input impedance, output resistance, voltage gain and phase shift as functions of frequency, amplifier input currents, offset voltage, common mode rejection ratio, and slew rate.