Skew Compensation Technique for Source-Synchronous Parallel DRAM Interface

Abstract

The interpin skew among the data and the strobe signals of a source-synchronous parallel DRAM interface is compensated by a simple delay-locked loop, which reuses the circuitry of a normal input data path. With the interpin skew compensation, the printed circuit board traces of the data and the strobe signals are allowed to have unequal length. The prototype implemented in a 0.13-mu m standard CMOS process shows that the interpin skew is reduced to be less than 26 ps for a 3.2-Gb/s/pin x8 parallel interface.