Double Data Rate I/O (ALTDDIO_IN, ALTDDIO_OUT, and ALTDDIO_BIDIR) IP Cores User Guide

ID 683148
Date 6/19/2017
Public
Document Table of Contents

1.2.1. DDR SDRAM, DDR2 SDRAM and RLDRAM II Memory

DDR SDRAM, DDR2 SDRAM, and RLDRAM II write and read data at twice the clock rate by capturing data on both the positive and negative edge of a clock.

DDR and DDR2 SDRAM are JEDEC standards. RLDRAM II devices have minimal latency to support designs that require fast response times. These DDR memory interfaces use a variety of I/O standards, such as SSTL-II, 1.8-V HSTL, LVTTL, and LVCMOS.