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Method for a DDR3/DDR2 combination motherboard

IP.com Disclosure Number: IPCOM000099059D
Publication Date: 2005-Mar-10
Document File: 3 page(s) / 176K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a double data rate memory (DDR3/DDR2) combination motherboard. Benefits include improved functionality, improved performance, and improved cost effectiveness.

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Method for a DDR3/DDR2 combination motherboard

Disclosed is a method for a double data rate memory (DDR3/DDR2) combination motherboard. Benefits include improved functionality, improved performance, and improved cost effectiveness.

Background

              As the memory industry transitions from DDR2 to DDR3 technology, a motherboard (MB) design is required that interfaces to both types of memory.

               Conventionally, signals travel different distances between two connectors on the MB. Additionally, the MB length is smaller than the signal wavelength. The result is phase distortion and decreased signal integrity.

              A DDR3 MB typically contains up to 3 separate memory channels. Having multiple channels enables upgradeability and increases the density of the system.

               

Description

              The disclosed method is the connection of DDR2 memory on a DDR3 motherboard. A riser card plugs into an existing DDR3 connector, Con1. On the riser card, DDR2 modules plug into two DDR2 connectors, Dcon1 and Dcon2, in a butterfly topology. Shock and vibration are improved by bolting the ends of the modules to the MB (see Figure 1). A second channel can be plugged into Con3 or Con2 on the bottom side of the MB (see Figure 2).

              The disclosed method can be implemented in several ways. For a DDR3 single DIMM per channel system, each DRAM module (UDIMM) receives its own set of signals, DQ/DQS/CMD/ADR/CTL/CK.

               Due to the higher channel speeds of DDR3 (800 MTS to 1600 MTS), only one memory module can be plugged into a channel. For example, a 3-channel DDR3 system can ha...