An on-chip clock-adjusting circuit with sub-100-ps resolution for a high-speed DRAM interface

Abstract

A novel fully digital fine-delay circuit for a high-speed DRAM interface is proposed. The circuit consists of arrayed delay components and generates a group of rail-to-rail delayed signals with sub-100-ps resolution. The input-coupling element (squeezer) in the delay component converges the variations of the resolution. A test device design using 0.35-/spl mu/m technology demonstrates that a resolution of 26 ps can be achieved. A clock-recovery circuit using this circuit has a two-clock-cycle lock time and sub-100-ps error.