A Multiphase DLL With a Novel Fast-Locking Fine-Code Time-to-Digital Converter

This brief presents a fast-locking multiphase closed-loop delay-locked loop (DLL). The proposed DLL employs a novel rapid-tracking time-to-digital converter that spends only two clock cycles to generate fine codes. This greatly reduces the fine-locking time and hence the total locking time that goes down to eight input reference clock cycles, shortened by 80%-95% compared with previously reported closed-loop architectures. Fabricated in a 130-nm technology, the proposed DLL operates at 80-450 MHz. In addition, the measured rms and peak-to-peak jitters at 180 MHz are 2.3 and 10 ps, respectively.