Wide band injection-locked quadrature frequency divider based on cmos ring oscillators

The design of an injection-locked frequency divider based on CMOS ring oscillators in a 0.25 mum CMOS technology is described. Analytical expressions for the noise performance and the locking band of the divider are derived. The divider, which has a division factor of four, can be used as a quadrature generator in a phase switching prescaler considerably lowering the prescaler total power consumption. The post-layout simulation results show that the divider can operate properly up to a maximum input frequency of 3 GHz, at 1.5 V power supply voltage, and with 0.53 mW power consumption, while its input locking range for -4 dBm injection signal level is more than 1 GHz