A 1-GHz LC voltage-controlled oscillator with high linearity and wide range

A 1-GHz low phase noise LC voltage-controlled oscillator (VCO) with high tuning linearity and wide range is presented. A novel resonant tank with a MOS varactor array and distributed control voltages is proposed to improve the tuning linearity and maintain a wide tuning range. Simulation results show that the tuning nonlinearity of the proposed VCO is only 0.8%, reduced by a factor of 4 compared with a conventional one. The VCO draws 5.2 mA current from a 1.8 V supply and can be tuned from 967 MHz to 1146 MHz (17%). The simulated phase noise is -132.2 dBc@1 MHz for an oscillation frequency of 1056 MHz.