Speed enhancement technique for divide-by-4 injection-locked frequency divider and its application to fractional division

A new cross-coupling method for the design of divide-by-4 injection-locked frequency divider (ILFD) is introduced for increased operation speed with no extra power consumption. Moreover, the proposed cross-coupled divide-by-4 ILFD is extended to the application of fractional divider based upon the phase-switching scheme. A prototype is fabricated in a standard 0.35 μm CMOS process. It exhibits an operation frequency range from 2.26 to 2.67 GHz and consumes less than 3.63 mW with a 1.5 V supply.