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W9725G8JB 8M 4 BANKS 8 BIT DDR2 SDRAM
Table of Contents1. 2. 3. 4. 5. 6. 7. 7.1 7.2 GENERAL DESCRIPTION ................................................................................................................... 4 FEATURES ........................................................................................................................................... 4 KEY PARAMETERS ............................................................................................................................. 5 BALL CONFIGURATION ...................................................................................................................... 6 BALL DESCRIPTION ............................................................................................................................ 7 BLOCK DIAGRAM ................................................................................................................................ 8 FUNCTIONAL DESCRIPTION .............................................................................................................. 9 Power-up and Initialization Sequence ................................................................................................... 9 Mode Register and Extended Mode Registers Operation ................................................................... 10 7.2.1 7.2.2 7.2.2.1 7.2.2.2 7.2.2.3 7.2.2.4 7.2.3 7.2.3.1 7.2.3.2 7.2.3.3 7.2.4 7.2.5 7.2.5.1 7.3 7.3.1 7.3.2 7.3.3 7.3.4 7.3.5 7.3.6 7.3.7 7.3.8 7.3.9 7.3.10 7.3.11 7.4 Mode Register Set Command (MRS)............................................................................... 10 Extend Mode Register Set Commands (EMRS) .............................................................. 11 Extend Mode Register Set Command (1), EMR (1) ................................................ 11 DLL Enable/Disable ................................................................................................ 12 Extend Mode Register Set Command (2), EMR (2) ................................................ 13 Extend Mode Register Set Command (3), EMR (3) ................................................ 14 Off-Chip Driver (OCD) Impedance Adjustment ................................................................ 15 Extended Mode Register for OCD Impedance Adjustment .................................... 16 OCD Impedance Adjust .......................................................................................... 16 Drive Mode ............................................................................................................. 17 On-Die Termination (ODT) ............................................................................................... 18 ODT related timings ......................................................................................................... 18 MRS command to ODT update delay ..................................................................... 18 Bank Activate Command.................................................................................................. 20 Read Command ............................................................................................................... 20 Write Command ............................................................................................................... 21 Burst Read with Auto-precharge Command..................................................................... 21 Burst Write with Auto-precharge Command ..................................................................... 21 Precharge All Command .................................................................................................. 21 Self Refresh Entry Command .......................................................................................... 21 Self Refresh Exit Command ............................................................................................. 22 Refresh Command ........................................................................................................... 22 No-Operation Command .................................................................................................. 23 Device Deselect Command .............................................................................................. 23
Command Function ............................................................................................................................. 20
Read and Write access modes ........................................................................................................... 23 7.4.1 7.4.1.1 Posted CAS .................................................................................................................... 23 Examples of posted CAS operation...................................................................... 23
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Publication Release Date: Oct. 12, 2010 Revision A01
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W9725G8JB
7.4.2 7.4..