Current-mode multiphase sinusoidal oscillator based on log-domain filtering

This paper describes the design of a multiphase sinusoidal oscillator (MSO) based on log-domain filtering concept. The circuit is a direct realization of a first-order differential equation for obtaining the inverting lossy integrators. Each integrator comprises only a grounded capacitor and four transistors per phase. The proposed MSO can be instantaneously controlled over a very wide frequency range by controlling a current for oscillation frequency and oscillation condition which are indicated proposed MSO suitability in high-frequency communications. The power consumption is obtained around 5.5 mW at 100 μA of bias current based on 2.5 V single power supply. The oscillation frequency is controlled over four decades of frequency. The total harmonic distortion of three-phases (11.5 MHz) is obtained around 2.4%.