10MHz to 7GHz Quadrature Signal Generation Using a Divide-by-4/3,-3/2,-5/3,-2,-5/2,-3,-4, and-5 Injection-Locked Frequency Divider

This paper presents a wideband LC-based VCO using a divide-by-fractional-N injection-locked frequency divider (ILFD), and the fractional-N division is realized by the proposed modulated injection technique. The feedback modulation of incident signals eliminates unwanted injections, which contributes to enlarge the locking range. The ILFD consists of a 2-stage differential ring oscillator, which achieves the multi-decade frequency tuning with quadrature outputs. The proposed circuit is implemented by using a 90 nm CMOS process, and the measured results achieves 10 MHz-to-7 GHz of continuous frequency tuning range with 9.6-15.6 mW of power consumption. The chip area is 250 x 200 mu m(2).