A wide locking range and low Voltage CMOS direct injection-locked frequency divider

A low voltage and wide locking range injection-locked frequency divider using a standard 0.18-μm complementary metal oxide semiconductor (CMOS) process is presented. The wide locking range and the low-voltage operation are performed by adding an injection nMOS between the differential outputs of the divider that contains on-chip transformers which result in positive feedback loops to swing the output signals above the supply and below the ground potential. This dual-swing capability maximizes the carrier power and achieves low-voltage performance. The measurement results show that at the supply voltage of 0.75-V, the divider free-running frequency is 2.02 GHz, and at the incident power of 0 dBm the locking range is about 1.49 GHz (36.88%), from the incident frequency 3.27 to 4.64GHz.