A fully integrated 2 GHz LC-VCO with phase noise of -125 dBc/Hz at 600kHz

A fully integrated 2 GHz very low phase noise LC-tank VCO is presented. Using only integrated planar inductors, the oscillator achieves phase noise as low as -125.1 dBc/Hz at 600 kHz offset and -138 dBc/Hz at 3 MHz. The excellent phase noise performance is achieved by means of an in-house developed simulator-optimizer, which determines the optimal coil parameters for a certain technology. To minimize the upconversion of flicker noise to 1/f³phase noise, a flicker noise upconversion factor is defined and optimized. While consuming 19mA from a 1.8V power supply, the oscillator exceeds DECT as well as DCS-1800 phase noise specifications. The VCO is implemented in a 0.65µm BiCMOS process.