6.1 GHz 4.6 mW CMOS divide-by-55/56 prescaler

A divide-by-55/56 phase switching prescaler based on odd phase signals is proposed. The odd phase signals for phase switching are generated by a divide-by-7 injection-locked frequency divider. A simple topology with a high operating frequency and a low power consumption is obtained. Implemented with a standard 0.18 m CMOS process, the prescaler is able to work from 3.2 to 6.1 GHz with a maximum measured power consumption of 4.6 mW from a 1.8 V supply voltage.