A 2.4GHz SiGe low phase-noise VCO using on chip tapped inductor

Abstract

An on-chip tapped inductor technique is shown to be an efficient method for reducing oscillator phase noise. Higher signal amplitude can be achieved while avoiding breakdown and without penalty in area or tuning range. A commercial SiGe BJT process was used to fabricate the 2.4GHz VCO. The measured phase noise at 1MHz offset frequency is -128 dBc/Hz with 23% tuning range. The VCO dissipates 16.5mA at a 2.5V supply voltage.