QVCO using back-gate connection for low power consumption and phase-noise reduction

This paper presents an analysis of phase noise in LC oscillators, and simulation results for CMOS quadrature-voltage-controlled-oscillator (QVCO) working in the 1.5-GHz frequency range. The phase noise data for a proposed BG-QVCO (-141 dBc/Hz at 1 MHz frequency offset from the carrier, for a power consumption of 5.4 mW). The noise of the coupling transistor is identified, and relationship between the phase noise and the ratio of the width of coupling transistor to the width of connecting transistor is analyzed. The prediction of the phase noise is in good agreement with the simulation results at the same offset frequency.