Measurement of Operational Amplifier Characteristics in the Frequency Domain

A test circuit for the automatic measurement of integrated-circuit operational amplifiers in the frequency domain has been developed. The main advantage of this test circuit over those previously reported in the literature is that it uses buffers in the feedback loop to reduce the influence of the output impedance of the operational amplifier. A fit program has been developed to extract the relevant parameters such as the transfer characteristics, the common mode rejection ratio, and the power supply rejection ratio. Examples of measurements are added for several operational amplifiers.