Current-feedback Op Amp Filter Theory And Application

The paper studies the theoretics and synthesis of current feedback operational amplifier (also called transirapedance operational amplifier, for short CFOA) and CFOA-C filter circuit, introduces the present state of the research of analogy integrated circuit. The model of bipolar junction transistor (BJT) and CMOS transistor and the basic circuit units such as current mirrors are briefly introduced; with the topology and model circuit, the principle and feature of the CFOA are analyzed. The simulative circuit of active network elements and analogue signal processing circuit are introduced. Simultaneously, the MOS-C-CFOA lossy integrator and MOS-C-CFOA lossless integrator and MOS-C-CFOA lossy summer integrator are proposed. The PSPICE simulation results of the new circuit are also given to confirm the theoretical analysis. In addition, realization of analogue divider and oscillator using CFOA is introduced. With internationally latest studies, the paper also proposes a universal filter which needs to change its input signal and a lowpass, bandpass and highpass filter which can be simultaneously realized, with no need for changing the topology of the circuit. Furthermore, new series R-L and C-D networks using a CFOA are presented. PSPICE simulation results of the proposed filter circuits are given to confirm the theoretical analysis.