Phase noise reduction in CMOS LC oscillators using tail noise shaping and Gm3 boosting

This paper presents a new technique for Low-Phase Noise CMOS Quadrature differential oscillator with better phase noise. The design uses tail noise shaping along with G_m3 boosting circuit and third harmonic tuned LC tank for improved phase noise performance. The proposed quadrature oscillator circuit shows a 4 dB phase noise improvement over standard fixed bias quadrature oscillator. Post Layout Simulation results in a 0.18-um CMOS fabrication process show that the phase noise of the proposed quadrature oscillator to be - 114 dBc/Hz at 1-MHz frequency offsets respectively at a center frequency of 5-GHz. The improvement is higher than the sum of reductions provided by the individual techniques. The power consumed increases by a very small amount and thus the Figure of Merit (FOM) shows a 4 dB improvement.