IMPLEMENTATION OF AN RF CMOS QUADRATURE LC VOLTAGE-CONTROLLED OSCILLATOR BASED ON THE SWITCHED TAIL TRANSISTOR TOPOLOGY

Abstract

This paper describes the design and implementation of an RF CMOS quadrature LC voltage-controlled oscillator in a 0.35 μm technology. The proposed oscillator employs the switched tail transistor topology and differential switch capacitor tuning to achieve low phase noise operation. A modified series coupling mechanism is used for quadrature signal generation with wide output signal swing. The oscillator core circuit was designed to operate with a 2.5 V power supply voltage with a 4 mA total supply current. Measurement results showed that the prototype oscillator could achieve a nominal oscillation frequency of 2.2 GHz with -110 dBc/Hz phase noise at 1 MHz offset frequency.