A single-chip low phase noise LC VCO for CMOS UHF RFID reader

A single-chip low power consumption and low phase noise LC VCO for CMOS UHF RFID reader is proposed in this paper. Requirements for VCO phase noise in UHF RFID reader are concluded based on the analysis of applications and system framework. LC filter and Low Drop-Output regulator are presented to suppress thermal noise from tail current and noise from power supply respectively. The proposed circuit is implemented with IBM 0.18 μm RF CMOS process. The VCO achieves a tuning range of 30% and phase noise of-136.25 dBc/Hz at a 1 MHz offset from 1.8 GHz carrier while drawing 4.5 mA from a 3.3 V power supply.