JEDEC Standard No. 209B
Contents
1 Scope ........................................................................................................................................1
2 Low-Power Double Data Rate (LPDDR) SDRAM Devices ...................................................2
2.1 Features..................................................................................................................................2
2.2 General Description ...............................................................................................................2
2.2.1 Packages..............................................................................................................................4
2.3 Terminology and Definitions.................................................................................................9
3 Functional Description............................................................................................................10
3.1 Initialization ........................................................................................................................10
3.1.0.1 TQ Signal Initialization .................................................................................................13
3.2 Register Definition...............................................................................................................13
3.2.1 Mode Register ..................................................................................................................13
3.2.1.1 Burst Length ..................................................................................................................14
3.2.1.2 Burst Type .....................................................................................................................16
3.2.1.3 Read Latency .................................................................................................................16
3.2.2 Extended Mode Register ..................................................................................................16
3.2.2.1 Partial Array Self Refresh (Optional) ...........................................................................17
3.2.2.2 Temperature Compensated Self Refresh (Optional) .....................................................17
3.2.2.3 Output Drive Strength ...................................................................................................17
3.2.3 Status Register Read (Optional)........................................................................................18
3.2.4 Temperature Output Signal (optional)..............................................................................20
4 Commands ..............................................................................................................................21
5 Operation.................................................................................................................................26
5.1 Deselect ...............................................................................................................................26
5.2 No Operation .......................................................................................................................26
5.3 Mode Register Set ...............................................................................................................26
5.4 Active ..................................................................................................................................27
5.5 Read ....................................................................................................................................28
5.5.1 Read to Read ....................................................................................................................30
5.5.2 Read Burst Terminate ......................................................................................................30
5.5.3 Read to Write ...................................................................................................................30
5.5.4 Read to Precharge ............................................................................................................30
5.5.5 Burst Terminate ................................................................................................................34
5.6 Write ....................................................................................................................................34
5.6.1 Write to Write ..................................................................................................................37
5.6.2 Write to Read ...................................................................................................................37
5.6.3 Write to Precharge: ..........................................................................................................37
5.7 Precharge .............................................................................................................................41
5.8 Auto Precharge ....................................................................................................................42
5.9 Refresh Requirements .........................................................................................................42
5.10 Auto Refresh .....................................................................................................................42
5.11 Self Refresh ........................................................................................................................42
-i-
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