An NIC‐improved balanced integrator and its application to filters

Abstract The authors have proposed a high‐frequency monolithic integrator in [1]. In the proposed circuit, lateral pnp transistors with less satisfactory high‐frequency response were utilized and they limited the high‐frequency response of the integrator. the response was improved by a passive compensation. However, it is difficult to determine the capacitance for the passive compensation. From such a viewpoint, this paper shows that an integrator with a balanced negative impedance converter can be constructed using only npn transistors. the computer analysis is made for the proposed integrator and the integrator proposed in [1], using SPICE 2G.1. It is shown that a performance better than that of the integrator in [1] is obtained without compensation owing to the elimination of pnp transistors. the proposed integrator was applied to the balanced third‐order low‐pass active RC filter system with a cutoff frequency of 1 MHz and with an automatically tunable function. an experiment was performed indicating the practical usefulness of the proposed integrator as well as the system.