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Company Profile

What is DDR3 Memory?

Tuesday, September 26, 2006

Several major DRAM manufacturer have made announcement, they are supplying the industry's first DDR3 devices and modules to leading PC industry developers for evaluation by early 2007.   Intelís Bearlake chipset will be the first to support DDR3 and it is expected to arrive in the third quarter of 2007 Key Features

  • The DDR3 components are twice as fast as today's highest speed DDR2 memory products.
  • The first computer systems equipped with the advanced DDR3 memory technology are expected to arrive in 2007.
  • The main advantages of DDR3 are the higher bandwidth and the increase in performance at low power.
  • The DDR3 SDRAM devices will offer data transfer rates up to 1600 Mbps (megabits per second).
  • The supply voltage for the memory technology is being reduced from 1.8 volts for DDR2 to just 1.5 volts for DDR3 targeting a work day equivalent of battery time. The voltage reduction limits the amount of power that is consumed and heat that is generated in connection with the increase in bandwidths.
Component densities: standardized from 512Mbit thru 8Gbit.
The most important densities will be 512Mbit and 1Gbit at the beginning, later on a 2Gbit and eventually 4Gbit component to follow.

Module densities: from 256MByte up to 8GByte for standard JEDEC modules.
Higher module densities beyond 8Gbyte for special applications like servers may be introduced later on.

Features*
DDR3 SDRAM Components:

  • Introduction of asynchronous RESET pin
  • Support of system level flight time compensation
  • On-DIMM Mirror friendly DRAM ballout
  • Introduction of CWL (CAS Write Latency) per speed bin
  • On-die IO calibration engine

DDR3 Feature Comparison

  DDR DDR2 DDR3*
Data Rate 200 ~ 400 Mbps 400 ~ 800 Mbps 800 ~ 1600 Mbps**
System Assumption

4slots(8loads)

2slots(4loads) 2slots(4loads)**
Vdd/Vddq 2.5v +/- 0.2V 1.8v +/- 0.1V 1.5v +/- 0.07V
Interface SSTL_2 SSTL_18 SSTL_15
Package 66TSOP2
60 BGA
60 BGA FOR 4/x8
84BGA FOR x16
78 BGA for x4/x8
96 BGA for x16
Source sync.

Bi-directional DQS
(Single ended Default)

Bi-directional DQS
(Single./Diff.Option)
Bi-directional DQS
(Differential Default)
Burst Length BL = 2,4,8
(2bits Prefetch)
BL = 4,8
(4bits Prefetch)
BL = 4,8
(8bits Prefetch)
# of bank 4banks 512Mb : 4banks
1Gb : 8banks
512Mb/1Gb : 8banks
2Gb/4Gb/8Gb : tbd
CL/tRCD/tRP ~15/15/15ns ~15/15/15ns ~12/12/12ns
Reset No No Yes
ODT No Yes Yes
Driver Calibration No Off-Chip Driver Calibration Self Calibration ZQ Pin
Leveling No No Yes

* : DDR3 Key Features Have been fixed in JEDEC.
** : Max. Frequency by DDR3 System Assumption is under discussion.
DDR3 supports 1600Mbps under 1slot/channel system.
And, the Possibility of DDR 2-slot/channel system being discussed in JEDEC.

DDR3 Modules:

  • Fly-by command/address/control bus with On-DIMM termination
  • High precision calibration resistors

Elpida DDR3 DIMM module

Advantages compared to DDR2

  • Higher bandwidth (up to 1600 Mbps)
  • Performance increase at low power
  • Longer battery life
  • Enhanced low power features and thermal design

DDR3 SDRAM will be packaged in a DIMM modules form factor.

 

DIMM Module Chip Type Clock Speed Data Rate Transfer Rate
PC3-6400 DDR3-800 400 800 6,400
PC3-8500 DDR3-1066 533 1066 8,530
PC3-10667 DDR3-1333 667 1333 10,660
PC3-12800 DDR3-1600 800 1600 12,800
PC3-14900 DDR3-1866 933 1866 14,930

Memory market research company iSuppli expected DDR3 DRAM products to replace their predecessor DDR2 as the main volume product in 2008. iSuppli forecasts a DDR3 market share of 55% the same year. IDC predicted that the first DDR3 memory will be commercially sold in 2006, whereas in 2009 market share of DDR3 will be 65%.

By: DocMemory
Copyright © 2006 CST, Inc. All Rights Reserved