A scalable low-voltage extended swing CMOS LC quadrature VCO for RF transceivers

This paper describes a novel scalable low voltage CMOS folded-cascode QVCO (quadrature voltage controlled oscillator) design using the TSMC 0.18 μm 5M1P CMOS process technology. The startup behavior of the proposed QVCO topology indicates that, the QVCO is free of bi-modal oscillation (frequency ambiguity). The VCO provided extended voltage swing with voltage supply scalable in the range 1.8V to 0.75V. The VCO operates in the range of 4GHz to 3GHz (corresponding to supply voltage scaling in the range 1.8V to 0.75V) with around 7% tuning range. The QVCO consumed under 5mW within the supply voltage scaling range. Phase noise simulations indicate a phase noise of around -165dBc/Hz at an offset of 600KHz from the carrier (@3.7GHz) for operation using the 1.8V supply voltage, which is quite favorable compared to other recent low-voltage QVCO designs.