2.4–10 GHz Low-Noise Injection-Locked Ring Voltage Controlled Oscillator in 90 nm Complementary Metal Oxide Semiconductor

Abstract

A wide-frequency-range low-phase-noise voltage controlled oscillator (VCO) with subharmonic injection locking is proposed and an implementation in 90 nm complementary metal oxide semiconductor (CMOS) is demonstrated. The result is a combination of the scalability and wide frequency tuning range naturally expected of a ring VCO and phase-noise performance close to that of an LC VCO using injection locking. The fabricated circuit is only 0.00054 mm2 in area, and its frequency tuning range is from 2.4 to 10 GHz. For a 500 MHz input reference signal and a 9.0 GHz (=18×500 MHz) output frequency, the 1-MHz-offset phase noise was -125 dBc/Hz. This is a 54 dB improvement over the free-running VCO phase noise of -71 dBc/Hz. The power consumption at 9.0 GHz is 9.5 mW.