A 470- $\mu{\hbox {W}}$ 5-GHz Digitally Controlled Injection-Locked Multi-Modulus Frequency Divider With an In-Phase Dual-Input Injection Scheme

This paper presents a digitally controlled injection-locked multimodulus frequency divider (ILMFD) based on a ring-oscillator using inverter chains for a small area and low power consumption. In the proposed ILMFD, division ratios of 2, 3, 4, 5 and 6 are achieved by using a programmable delay line that changes the self-oscillation frequency of the ring-oscillator. The locking range of the proposed ILMFD is improved by employing a dual-input injection scheme, which unlike previous multiinput injection schemes, does not require distinct phase inputs. A prototype chip implemented in a 0.13-μm CMOS process has an area of 35×33 μm² and operates at 5 GHz while consuming 470 μW from 1.2 V supply, where 350 μW is dissipated in the core of the ILMFD. The proposed divider is the first reported multimodulus ILFD with digitally controlled division ratios and an in-phase dual-input injection scheme.