Design methodology for a divide-by-4 LC injection-locked frequency divider based on nonlinear analysis

One significant source of power consumption in modern frequency synthesizers at high frequencies is the prescaler block. In order to tackle this problem, analog injection-locked frequency dividers (ILFDs) have been considered rather than conventional digital prescalers. In recent years, diverse and sometimes contradictory algorithms for estimating the locking range in these dividers have been proposed. In this paper, we propose a new method based on nonlinear analysis to design a typical (LC oscillator-based) injection-locked frequency divider and to predict its locking range. In order to support our analysis, we design a divide-by-4 circuit and compare its simulated locking range with theoretical predictions.