A Wide Locking Range and Low Power Divide-by-2/3 LC Injection-Locked Frequency Divider

A direct divide-by-2/3 LC injection-locked frequency divider (ILFD) is presented in this paper. The proposed ILFD circuit is based on a CMOS LC tank oscillator coupled with an injection NMOS transistor in series with an inductor. Together with body-biased technique and current-reused topology, the locking range of the ILFD is improved and the power consumption is reduced. The circuit is implemented in a 0.18 mu m standard RF CMOS process. At the incident power of 0 dBm, the measured locking range of the divide-by-2 and divide-by-3 modes are from 5.37 GHz to 7.68 (8.07GHz to 11.4 GHz) GHz, and the core circuit without buffers consumes 3 mW at the supply voltage of 1.5 V. The chip only occupies 0.23 x 0.8 mm(2) without the pads and the buffers.