2 GHz sub‐harmonically injection‐locked PLL with mixer‐based injection timing control in 0.18 µm CMOS technology

A 2 GHz sub‐harmonically injection‐locked phase‐locked loop (SILPLL) with a self‐aligned injection window is presented. The SILPLL adopts a mixer‐based self‐align technique to automatically adjust the injection timing, overcoming the speed limitation of the phase detection. Circuit techniques such as a symmetrical mixer and a V/I converter with mismatch cancellation are adopted to improve injection timing accuracy. Fabricated in a 180 nm CMOS technology, the SILPLL exhibits −127 dBc/Hz phase noise at 1 MHz offset and draws 6.9 mA current from a 1.8 V power supply. The measured root‐mean‐square jitter integrating from 1 kHz to 40 MHz is 214 fs and the reference spur is −61 dBc.