A 0.5 V, 9-GHz Sub-Integer Frequency Synthesizer Using Multi-Phase Injection-Locked Prescaler for Phase-Switching-Based Programmable Division With Automatic Injection-Lock Calibration in 45-nm CMOS

A 9-GHz sub-integer frequency synthesizer incorporates a multi-phase injection-locked ring-oscillator-based prescaler for operation at an ultra-low supply voltage of 0.5 V, phase-switching-based programmable division for sub-integer frequency synthesis, and automatic calibration to ensure injection lock. The synthesizer consumes 3.5 mW of power at 9.12 GHz and 0.05 mm(2) of area, while showing an output phase noise of -100 dBc/Hz at 1 MHz offset and RMS jitter of 325 fs; it achieves a net FOMA of -186.5 in a 45-nm SOI CMOS process.