Voltage-Controlled Oscillator with a Trifilar-Transformer

This letter designs an inductance-capacitance (LC) CMOS NP-cross-coupled voltage-controlled oscillator (VCO) using a new trifilar LC resonator. The voltage-biased VCO uses a new two-turn octagonal inductor and a pair of varactors to form the primary resonator. The die area of the VCO in the 0.18μm CMOS process is 0.766 ×1.026 mm2. The measured oscillation frequency of the VCO is 5.71 GHz, the phase noise at 1 MHz offset is −114.812 dBc/Hz. and the figure of merit (FOM) is −190.04 dBc/Hz at the power consumption of 0.978 mW. The degenerated-source inductors boost the voltage swing and lowers the power dissipation.