A CMOS DLL-based 120MHz to 1.8GHz clock generator for dynamic frequency scaling

Abstract

A DLL-based clock generator for dynamic frequency scaling is fabricated in a 0.35 /spl mu/m CMOS technology. It generates clock signals ranging from 120MHz to 1.8GHz. The frequency can be dynamically changed. If the clock generator scales its output frequency dynamically by programming with the same last bit, it takes only one clock cycle to lock. The proposed clock generator has a jitter of /spl plusmn/6.6ps/sub pp/ at 1.3GHz.