A CMOS Direct Injection-Locked Frequency Divider With High Division Ratios

Abstract

A CMOS injection-locked frequency divider (ILFD) with high division ratios and high frequency operation is presented. It consists of a ring oscillator and injection capacitors. An input signal is directly injected through the capacitors into the feedback nodes of the ring oscillator. The proposed ILFD is fabricated in a 0.18 mu m CMOS process and has a chip core size of 68 mu m x 70 mu m. It shows multiple division ratios of 3, 6, and 9. The operation frequency is from 2.2 to 30.95 GHz. At the maximum operation frequency, the ILFD has a locking range of 260 MHz with an input power of less than 0.25 dBm, a division ratio of 9, and a power consumption of 12.5 mW. The locking range increases up to 3.2 GHz as the division ratio and the operation frequency decrease.