Phase Noise Performance Analysis of High Speed Cross Coupled CMOS LC VCOs

This paper reports a phase noise analysis of high speed cross-coupled LC Voltage Controlled Oscillators at 1-GHz, 10-GHz and 20-GHz carrier frequency operation, designed in a 65 nm CMOS process, commercially available by TSMC. Detailed noise simulation analysis is performed in relation to phase noise performance optimization in all three VCOs, setting specific comparison constraints such as keeping identical transistor sizing and bias settings while only modifying the passive LC tank. All the noise contributing sources-thermal, flicker and gate noise - are analyzed as to extract noise optimization trends in terms of the VCO operating frequency versus the overall phase noise.