A 2.4-GHz, Wide Tuning Range GmC VCO Using a Novel Load Biasing Technique

This paper presents a 2.4-GHz monolithic GmC fully differential voltage controlled oscillator (VCO) fabricated in 0.24-mum CMOS technology with a wide tuning range between 1.77 GHz and 2.73 GHz. This VCO can be used for data clock recovery applications in optical receivers for such standards as SONET OC-48 or European SDH STM-16. Two published techniques for quadrature generation are discussed for use in data clock recovery. The circuit implementation is purely transistor based OTA stages with the entire VCO covering 60 mum x 90 mum. A novel technique for active load biasing is introduced which provides marginal temperature insensitivity and eliminates a need for external bias source. The power dissipation is less than 50 mW at 2.0 V power supply and the measured phase-noise is -93 dBc/Hz at 2 MHz offset.