Low-Voltage, Wide-Locking-Range, Millimeter-Wave Divide-by-5 Injection-Locked Frequency Dividers

A new injector topology is proposed for the design of CMOS millimeter-wave divide-by-5 injection-locked frequency dividers (ILFDs). The topology is based on a distributed-element harmonic termination by an open-stub structure connected to the floating source end of the differential injection pair. ILFDs operating at 24 and 60 GHz are demonstrated in this study. The new topology combined with an N-MOS cross-coupled oscillator core can greatly reduce the supply voltage and power consumption requirement of the divider. The simulated results indicate that, by using the distributed-element harmonic termination, the locking range can be improved by over 40 and 72% for the 24- and 60-GHz operations, respectively. The test circuits for the 24- and 60-GHz ILFDs are implemented by a 0.18-m and 90-nm CMOS process, respectively. The power consumption is 7.4 and 3.75 mW at a supply voltage of 0.7 and 0.6 V, with a very wide locking range of 1.9 and 4.1 GHz, for the 24- and 60-GHz ILFDs, respectively. The proposed 24- and 60-GHz divide-by-5 ILFDs have the outstanding figure-of-merit (FOM) values of 6.4 and 69.4, respectively, compared with reported works.