An eight-phase CMOS injection locked ring oscillator with low phase noise

This paper presents the design of a low DC power, low phase noise single-ended ring oscillator (RO) in 0.18 μm CMOS technology. It introduces a new RO output phase control technique. This RO uses a voltage pull-down circuit to produce different output signal phases. The proposed RO employs the pulse injection (PI) technique for phase noise and spurious signals suppression. The proposed injection locked ring oscillator (ILRO) can be used for phase shift keying (PSK) implementation. The proposed ILRO has an oscillation frequency of 4.5 GHz with a fine tuning range of 540 MHz. It consumes only a 4.25 mW of power while having a phase noise of −130.9 dBc/Hz @ 1MHz offset. Through this ILRO design, a figure of merit (FoM) of −197.68 dBc/Hz has been achieved.