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 FOM
_A
of -186.5 in a 45-nm SOI CMOS process.