Analysis and implementation of a 0.9-V voltage-controlled oscillator with low phase noise and low power dissipation

A voltage-controlled oscillator (VCO) with low phase noise and low power dissipation for IEEE 802.11b is proposed. A negative resistance multiple-gated circuit with a bypass capacitor is adopted to improve phase noise. The chip is implemented in 0.18-μm CMOS process under a supply voltage of 0.9 V and power consumption of 2.7 mW. Its measured results show that the VCO has a phase noise of - 122.3 dBc/Hz at 1-MHz offset frequency from the carrier frequency, and the tuning frequency from 2.17 to 2.73 GHz can be obtained under the tuning voltage of - 0.9 to 0.9 V. The theoretical analysis and design consideration are also conducted in detail to show the benefits of the proposed VCO.