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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. Intel’s 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

~12/12/12ns

Reset

Yes

ODT

Yes

Driver Calibration

Off-Chip Driver Calibration

Self Calibration ZQ Pin

Leveling

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%.