A UHS-II SD card controller with 240MB/s write throughput and 260MB/s read throughput

Abstract

This paper presents a UHS-II SD card controller with 240MB/s write and 260MB/s read throughput. Two opposite direction IO lanes for down- and up-streams are quickly switched as single direction for double data rate, without adding extra IO pins. The proposed clock data recovery (CDR) logic can detect symbols within 20ns and minimizes this lane switching overhead. The developed SLVS-type driver that can reduce the common to differential return loss by 15dB is also introduced to improve the noise tolerance.