A 370μW Ring VCO Based Injection-Locked Frequency Synthesizer for GPS Receiver

An ultra-low power ring-type voltage controlled oscillator (VCO) based frequency synthesizer for Ll band Global Positioning System (GPS) receiver is presented in this paper. To minimize the power consumption and enlarge the multiple factor, we propose a four times frequency multiplier before the injection-locked oscillator (ILO), which consist of a passive poly-phase filter and an edge combiner. A continuous frequency tracking loop (FTL) is also implemented to calibrate the free-running frequency of injection-locked oscillator by using the quadrature outputs of ILO. The proposed injection-locked frequency synthesizer achieves −115dBc in-band phase noise and $370\mu \mathrm{W}$ power consumption, which profit from the pre-frequency multiplier and the FTL. The proposed frequency synthesizer is demonstrated in a 65nm CMOS technology. The integrated jitter is 2.7ps and the figure of merit (FOM) is −235.6dB.