External Memory Interface Handbook Volume 2: Design Guidelines: For UniPHY-based Device Families

ID 683385
Date 3/06/2023
Document Table of Contents Address and Command Signals

Two UDIMMs result in twice the effective load on the address and command signals, which reduces the slew rate and makes it more difficult to meet setup and hold timing (tIS and tIH). However, address and command signals operate at half the interface rate and are SDR. Hence a 400-Mbps data rate equates to an address and command fundamental frequency of 100 MHz.