A low phase noise, high figure of merit, 3.1 GHz–3.5 GHz ring oscillator using edge injection technique

This paper presents the design of low phase noise, high figure of merit (FoM), and low power injection locked ring oscillator (ILRO) in 0.18 μm CMOS technology. Edge injection technique has been adopted for ring oscillator (RO) phase noise suppression and performance enhancement. Edge injection helps improving the oscillator jitter performance while maintaining spurious harmonics minimized. In addition, implementing the proposed RO using identical NAND delay stages simplifies the design and improves frequency oscillation adjustment. The proposed injection locked oscillator (ILO) has an oscillation frequency of 3.3 GHz with fine tuning range of 400 MHz. This ILO achieves a phase noise of −120.2 dBc/Hz at 1 MHz offset. It consumes only 4.4 mW from a 1.8 V DC power source. The proposed ILRO can achieve a FoM of −184.1 dBc/Hz.