参数资料
型号: W9712G6JB-3
厂商: WINBOND ELECTRONICS CORP
元件分类: DRAM
英文描述: 8M X 16 DDR DRAM, 0.45 ns, PBGA84
封装: 12.50 X 8 MM, ROHS COMPLIANT, WBGA-84
文件页数: 15/86页
文件大小: 1027K
代理商: W9712G6JB-3
W9712G6JB
Publication Release Date: Mar. 15, 2010
- 22 -
Revision A01
commands must be registered on each positive clock edge during the Self Refresh exit interval tXSNR.
ODT should be turned off during tXSRD.
The use of Self Refresh mode introduces the possibility that an internally timed refresh event can be
missed when CKE is raised for exit from Self Refresh mode. Upon exit from Self Refresh, the DDR2
SDRAM requires a minimum of one extra auto refresh command before it is put back into Self Refresh
mode.
7.3.9
Refresh Command
( CS = "L", RAS = "L", CAS = "L", WE = "H", CKE = "H", BA0, BA1, A0 to A11 = Don’t Care)
Refresh is used during normal operation of the DDR2 SDRAM. This command is non persistent, so it
must be issued each time a refresh is required.
The refresh addressing is generated by the internal refresh controller. This makes the address
bits ”Don’t Care” during an Auto Refresh command. The DDR2 SDRAM requires Auto Refresh cycles
at an average periodic interval of
tREFI (max.).
When the refresh cycle has completed, all banks of the DDR2 SDRAM will be in the precharged (idle)
state. A delay between the auto refresh command (REF) and the next activate command or
subsequent auto refresh command must be greater than or equal to the auto refresh cycle time (tRFC).
To allow for improved efficiency in scheduling and switching between tasks, some flexibility in the
absolute refresh interval is provided. A maximum of eight Refresh commands can be posted to any
given DDR2 SDRAM, meaning that the maximum absolute interval between any Refresh command
and the next Refresh command is 9 x tREFI.
T0
T1
T2
T3
CLK/CLK
CKE
CMD
≥ tRP
≥ tRFC
NOP
ANY
REF
Precharge
"HIGH"
Tm
Tn
Tn + 1
Figure 13—Refresh command
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W9712G6KB-25 制造商:Winbond Electronics Corp 功能描述:128M DDR2-800, X16 制造商:Winbond Electronics 功能描述:IC MEMORY 制造商:Winbond Electronics Corp 功能描述:IC MEMORY
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W9712G8JB 制造商:WINBOND 制造商全称:Winbond 功能描述:4M × 4 BANKS × 8 BIT DDR2 SDRAM
W9712G8JB25 制造商:Winbond Electronics Corp 功能描述:DRAM Chip DDR2 SDRAM 128M-Bit 16Mx8 1.8V 60-Pin WBGA
W9712G8JB25I 制造商:Winbond Electronics Corp 功能描述:128M DDR2-800, X8, IND TEMP