W9725G6JB
4M 4 BANKS 16 BIT DDR2 SDRAM
Table of Contents1.
GENERAL DESCRIPTION ................................................................................................................... 4
2.
FEATURES ........................................................................................................................................... 4
3.
KEY PARAMETERS ............................................................................................................................. 5
4.
BALL CONFIGURATION ...................................................................................................................... 6
5.
BALL DESCRIPTION ............................................................................................................................ 7
6.
BLOCK DIAGRAM ................................................................................................................................ 8
7.
FUNCTIONAL DESCRIPTION .............................................................................................................. 9
7.1
7.2
Power-up and Initialization Sequence ................................................................................................... 9
Mode Register and Extended Mode Registers Operation ................................................................... 10
7.2.1
Mode Register Set Command (MRS)............................................................................... 10
7.2.2
Extend Mode Register Set Commands (EMRS) .............................................................. 11
7.2.2.1
Extend Mode Register Set Command (1), EMR (1)................................................ 11
7.2.2.2
DLL Enable/Disable ................................................................................................ 12
7.2.2.3
Extend Mode Register Set Command (2), EMR (2) ................................................ 13
7.2.2.4
Extend Mode Register Set Command (3), EMR (3) ................................................ 14
7.2.3
Off-Chip Driver (OCD) Impedance Adjustment ................................................................ 15
7.2.3.1
Extended Mode Register for OCD Impedance Adjustment .................................... 16
7.2.3.2
OCD Impedance Adjust .......................................................................................... 16
7.2.3.3
Drive Mode ............................................................................................................. 17
7.2.4
On-Die Termination (ODT) ............................................................................................... 18
7.2.5
ODT related timings ......................................................................................................... 18
7.2.5.1
7.3
MRS command to ODT update delay ..................................................................... 18
Command Function ............................................................................................................................. 20
7.3.1
Read Command ............................................................................................................... 20
7.3.3
Write Command ............................................................................................................... 21
7.3.4
Burst Read with Auto-precharge Command..................................................................... 21
7.3.5
Burst Write with Auto-precharge Command ..................................................................... 21
7.3.6
Precharge All Command .................................................................................................. 21
7.3.7
Self Refresh Entry Command .......................................................................................... 21
7.3.8
Self Refresh Exit Command ............................................................................................. 22
7.3.9
Refresh Command ........................................................................................................... 22
7.3.10
No-Operation Command .................................................................................................. 23
7.3.11
7.4
Bank Activate Command.................................................................................................. 20
7.3.2
Device Deselect Command .............................................................................................. 23
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: Nov. 29, 2011
Revision A02