Operational Current Amplifiers-Based Quadrature Oscillators Family

Abstract

This idea presents a novel family of current-mode quadrature oscillators (CMOS) employing operational current amplifiers (OCAS) as the active building blocks. The proposed oscillator configurations generate two sinusoidal output currents with a precise 90° phase difference, making them highly suitable for quadrature signal generation in communication and instrumentation systems. The circuit topologies are systematically derived to achieve high design flexibility, a low number of active and passive components, and convenient electronic tunability. Analytical derivations for the condition of oscillation (co) and frequency of oscillation (fo) are provided, demonstrating independent control of both parameters through biasing currents or transconductance adjustment. The circuits operate under low supply voltages, making them ideal for modern low-power analog signal processing applications. Simulation results obtained using tanner eda 16.1 with standard CMOS OCA implementations validate the theoretical predictions, confirming low total harmonic distortion, a wide frequency tuning range, and excellent phase accuracy. Experimental results further verify the feasibility and performance of the proposed designs, establishing the presented family as a robust and versatile solution for current-mode quadrature oscillator realization.