Composite operational amplifiers: Generation and finite-gain applications

A practical and effective general approach is presented for extending the useful operating frequencies and improving the performance of linear active networks realized using operational amplifiers (OA\´s). This is achieved by replacing each OA in the active network by a composite operational amplifier (CNOA) constructed using OA\´s. The technique of generating the CNOA\´s for any given is proposed. The realizations employing the CNOA are examined according to a stringent performance criterion satisfying such important properties as extended bandwidth, stability with one- and two-pole OA models, low sensitivity to the components and OA mismatch, and wide dynamic range. Several families of CNOA\´s, for and , are shown to satisfy ,the suggested performance criterion. In this contribution, the CNOA\´s applications in inverting, noninverting, and differential finite-gain amplifiers are given and shown theoretically and experimentally to compare favorably with the state-of-the-art realizations using the same number of OA\´s. Applications of the CNOA in inverting integrator and active filter realizations are presented in a companion contribution [32].