A wide-band divide-by-3 injection-locked frequency divider using tunable MOS resistor

A wide locking range/operation range parallel resonant divide-by-3 injection-locked frequency divider (ILFD) using a standard 0.18 μm CMOS process is presented. The divide-by-3 ILFD circuit is realized with a parallel resonant cross-coupled n-core MOS LC-tank oscillator. A MOSFET is used as a resistor to degrade the resonator quality factor and enhance the locking range and it is also used to tune the oscillation frequency and widens the operation range. Two direct-injection MOSFETs in series are used as a frequency doubler and quadrupler, and a dynamic linear mixer to widen the locking range. The core power consumption of the ILFD core is 4.896 mW. At the incident power of 0 dBm, and the supply voltage of 0.8 V, the maximum locking range is 1.6 GHz, from 10.6 GHz to 12.2 GHz and the operation range percentage of 47.6%, from 5 GHz to 13 GHz.