A 1.0 V 10.2 GHz CMOS frequency divider with differential injection locking

Improving the performance of the frequency synthesizer is indispensable for improving the performance of RF transceiver circuits. A voltage-controlled oscillator (VCO) and a frequency divider (FD) operating at full speed are key components for improving frequency synthesizer performance. We have fabricated a high-speed FD using newly proposed differential injection locking. Differential injection locking is a circuit that locks the phase of the differential output of an oscillator to be synchronized with the input signal. Differential injection locking is explained and the experimental results for the proposed FD are discussed. As a result of applying differential injection locking to a three-stage ring oscillator, a maximum dividing frequency of 10.2 GHz was achieved at a supply voltage of 1 V. Since it is theoretically independent of the oscillator topology, differential injection locking can also be applied to an LC oscillator and a differential ring oscillator when differential outputs are necessary. It will be possible to demonstrate the validity of differential injection locking for any kind of oscillator.