A 1V CMOS quadrature LC VCO using diode coupling

A new quadrature VCO is designed in a standard UMC 0.13 μm CMOS process with low voltage, low power and low phase noise. Diodes are employed to generate second-harmonic coupling between the common sources of two LC VCOs for quadrature outputs. At 1-V supply and at 3.9GHz, the QVCO measures phase noise of −117dBc/Hz at 1-MHz offset while dissipating 7.5mA which corresponds to a figure of merit of 180dBc. The core area is 0.37mm
²
.