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

ID 683385
Date 3/06/2023
Document Table of Contents

3. Dual-DIMM DDR2 and DDR3 SDRAM Board Design Guidelines

The following topics describe guidelines for implementing dual unbuffered DIMM (UDIMM) DDR2 and DDR3 SDRAM interfaces.

The following topics discuss the impact on signal integrity of the data signal with the following conditions in a dual-DIMM configuration:

  • Populating just one slot versus populating both slots
  • Populating slot 1 versus slot 2 when only one DIMM is used
  • On-die termination (ODT) setting of 75-ohm versus an ODT setting of 150-ohm

For detailed information about a single-DIMM DDR2 SDRAM interface, refer to the DDR2 and DDR3 SDRAM Board Design Guidelines chapter.