Abstract

Objective: A tunable CMOS active inductor/resonator based Voltage Controlled Oscillator (VCO) has been presented. In the design of LC-VCO, LC resonator (tank) circuit has been substituted with gyrator based CMOS active inductor/resonator. The purity of VCO output signal is defined by the phase noise parameter.

Methods: For good spectral purity of VCO output signal, the phase noise should be minimum. Moreover, the quality factor of LC resonator is inversely proportional to the phase noise of VCO output signal. In the presented work, a high-quality active inductor/resonator circuit has been used to design VCO which minimizes the phase noise and chip area as well. Further, other VCO characterization factors are measured.

Results: The designed circuit has been implemented in 0.18µm CMOS technology.

Conclusion: The design of the proposed AI based voltage controlled oscillator shows better phase noise, less chip area and high output power. The high output power is achieved at the cost of limited tuning range of 1.14 GHz ~ 2.1 GHz. The presented active inductor based voltage controlled oscillator can be used for RF applications from 1.14GHz ~ 2.1GHz.

Keywords: Active Inductor (AI), compact, phase noise, tuning range, quality factor, Voltage Controlled Oscillator (VCO), widlar current source.