The Secrets of PC Memory: Part 1

Written by Ryan J. Leng

November 15, 2007 | 10:43

Tags: #background #ddr #ddr2 #ddr3 #details #ryan #technology

FeaturesUnitDDR1DDR2DDR3
Connecting Pins
DIMM184240240
SO-DIMM100 200200204
Registered DIMM184240240
Mini-DIMM-244-
Micro-DIMM172214-
Packaging60-pin TSOP2 / 60-pin FBGA / LQFP60/84-pin FBGA78/96-pin FGBA / FBGA with Mirroring
Lengthmm
DIMM133.35 (5.25)133.35 (5.25)133.35 (5.25)
SO-DIMM66.7 (2.625)66.7 (2.625)66.7 (2.625)
Registered DIMM133.35 (6.25)133.35 (6.25)133.35 (6.25)
Mini-DIMM-82 (3.23)83 (3.23)
Micro-DIMM54 (2.13)54 (2.13)54 (2.13)
Dram Core FreqMHz100 - 200100 - 200100 - 200
TopologyAsymmetric T-Branch
(T-Daisy)
Symmetric T-BranchFly-By with Termination
JEDEC Classified Data RateDDR-200/266/333/400DDR2-400/533/667/800DDR3-800/1066/1333/1600
Prefetch Widthbits248
Bandwidth (theoretical)GB/s
Single-Channel1.6 / 2.13 / 2.67 / 3.23.2 / 4.26 / 5.34 / 6.46.4 / 8.53 / 10.67 / 12.8
Dual-Channel2.2 / 4.26 / 5.32 / 6.46.4 / 8.52 / 10.68 / 12.812.8 / 17.06 / 21.34 / 25.6
Module Capacity128MB - 1GB256MB - 4GB (8GB)512MB - 8GB (16GB)
Number of Banks44 or 88
Read/Write LevelingNoNoYes
Supply VoltageVolts2.5 +/- 0.21.8 +/- 0.11.5 +/- 0.075
Max Operating TempºC (ºF)85 (185)85 (185)85 (185)
I/O Widthx4 / x8 / x16x4 / x8 / x16x4 / x8 / x16 / x32
DIMM Calibration ResistorsNoNoYes
Burst Length2, 44, 84 (Burst Chop), 8
RHoSVendor DependentVendor DependentVendor Dependent
Latency
CAS Latency (CL)tCK2, 2.5, 3(2), 3, 4, 5, 65, 6, 7, 8, 9, 10, (11)
Additive Latency (AL)tCK-0, 1, 2, 3, 40, 1, 2
READ Latency (RL)tCKCLCL+ALCL+AL
WRITE Latency (WL)tCK1RL-15, 6, 7, 8
CAS Write Latency (CWL)tCK--5, 6, 7
DQ Timing
READDLL aligns DQ, DQS to CKDLL aligns DQ, DQS, DQSb, RDQS to CKDLL aligns DQ, DQS, DQSb to CK
WRITESetup / Hold to DQSSetup / Hold to DQS DQSbSetup / Hold to DQS DQSb
Data StrobesSingle-ended data strobeSingle-ended or Differential data strobeDifferential data strobe with WRITE leveling
TerminationMotherboard ChipsetOn-Die TerminationDynamic On-Die
Driver CalibrationNoOff-Chip Driver (OCD)On-Chip Self-Calibration with ZQ pin
DQ Driver StrengthNarrow Envelope18 +/-3 Ohms, OCD Calibration30-40 Ohms, ZQ pin Calibration
InterruptsYesWr-Wr, Rd-Rd (4n only)Burst Chop for Rd and Wr
Reset FunctionNoNoYes (Asynchronous)
Thermal SensorNoSO-DIMM (on DIMM),
FB-DIMM (on Die)
SO-DIMM (on DIMM),
FB-DIMM (on Die)
Automatic Self Refresh (ASR)SupportedSupportedSupported
Temp. Compensated Self Refresh (TCSR)SupportedSupportedSupported
Self Refresh Temp (SRT)<= 85 ºC<= 95 ºC<= 85 ºC, <= 95 ºC
Partial Array Self Refresh (PASR)SupportedSupportedSupported
Deep Power Down (DPD)SupportedSupportedSupported
Clock Stop ModeSupportedSupportedSupported

Data Sources: JEDEC, Altera Corporation, Elpida Memory, Infineon Technologies, Kingston Technology, Micron Technology, MOSAID Technologies, Qimonda, Rambus, Samsung Semiconductor, Via Technology

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