A 15-GHz, 17.8-mW, 213-fs Injection-Locked PLL With Maximized Injection Strength Using Adjustment of Phase Domain Response

This brief presents an injection-locked PLL (ILPLL) that offers better jitter performance for high-speed clock generation. By analyzing and adjusting a phase domain response (PDR) of the injection-locked oscillator (ILO), the injection strength at the target frequency of 15 GHz is maximized with the lowest deterministic noise. In addition, a pulse generator that limits the maximum operating speed in the conventional ILPLL is removed to achieve the highest synthesizable clock frequency. Fabricated in 28-nm CMOS technology, the proposed ILPLL occupies an active area of 0.03 mm
²
and dissipates 17.8 mW at 15 GHz with a 1.3-V supply voltage. The measured integrated jitter from 1 kHz to 40 MHz at the point of maximum injection strength is 213 fs and the corresponding reference spur level is -43 dBc.