- 您现在的位置：买卖IC网 > Sheet目录369 > W9725G6KB-25I (Winbond Electronics)IC DDR2 SDRAM 256MBIT 84WBGA
W9725G6KB
8. FUNCTIONAL DESCRIPTION
8.1
Power-up and Initialization Sequence
DDR2 SDRAMs must be powered up and initialized in a predefined manner. Operational procedures
other than those specified may result in undefined operation. The following sequence is required for
Power-up and Initialization.
1. Apply power and attempt to maintain CKE below 0.2 × V DDQ and ODT *1 at a LOW state (all other
inputs may be undefined.) Either one of the following sequence is required for Power-up.
A. The V DD voltage ramp time must be no greater than 200 mS from when V DD ramps from 300
mV to V DD min; and during the V DD voltage ramp, |V DD -V DDQ | ≤ 0.3 volts.
?
?
?
?
V DD , V DDL and V DDQ are driven from a single power converter output
V TT is limited to 0.95V max
V REF *2 tracks V DDQ /2
V DDQ ≥ V REF must be met at all times
B. Voltage levels at I/Os and outputs must be less than V DDQ during voltage ramp time to avoid
DRAM latch-up. During the ramping of the supply voltages, V DD ≥ V DDL ≥ V DDQ must be
maintained and is applicable to both AC and DC levels until the ramping of the supply voltages
is complete.
?
?
?
?
?
?
Apply V DD /V DDL *3 before or at the same time as V DDQ
Apply V DDQ *4 before or at the same time as V TT
V REF *2 tracks V DDQ /2
V DDQ ≥ V REF must be met at all times.
Apply V TT
The V TT voltage ramp time from when V DDQ min is achieved on V DDQ to when V TT min is
achieved on V TT must be no greater than 500 mS
2. Start Clock and maintain stable condition for 200 μS (min.).
3. After stable power and clock (CLK, CLK ), apply NOP or Deselect and take CKE HIGH.
4. Wait minimum of 400 nS then issue precharge all command. NOP or Deselect applied during 400
nS period.
5. Issue an EMRS command to EMR (2). (To issue EMRS command to EMR (2), provide LOW to
BA0, HIGH to BA1.)
6. Issue an EMRS command to EMR (3). (To issue EMRS command to EMR (3), provide HIGH to
BA0 and BA1.)
7. Issue EMRS to enable DLL. (To issue DLL Enable command, provide LOW to A0, HIGH to BA0
and LOW to BA1. And A9=A8=A7=LOW must be used when issuing this command.)
8. Issue a Mode Register Set command for DLL reset. (To issue DLL Reset command, provide HIGH
to A8 and LOW to BA0 and BA1.)
9. Issue a precharge all command.
10. Issue 2 or more Auto Refresh commands.
11. Issue a MRS command with LOW to A8 to initialize device operation. (i.e. to program operating
parameters without resetting the DLL.)
12. At least 200 clocks after step 8, execute OCD Calibration (Off Chip Driver impedance adjustment).
If OCD calibration is not used, EMRS to EMR (1) to set OCD Calibration Default
(A9=A8=A7=HIGH)
followed by EMRS to EMR
(1) to exit OCD Calibration Mode
(A9=A8=A7=LOW) must be issued with other operating parameters of EMR(1).
13. The DDR2 SDRAM is now ready for normal operation.
Publication Release Date: Sep. 03, 2012
-9-
Revision A03
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
W972GG6JB-3I
IC DDR2 SDRAM 2GBITS 84WBGA
W9751G6IB-25
IC DDR2-800 SDRAM 512MB 84-WBGA
W9751G6KB-25
IC DDR2 SDRAM 512MBIT 84WBGA
W9812G6JH-6I
IC SDRAM 128MBIT 54TSOPII
W9816G6IH-6I
IC SDRAM 16MBIT 50TSOPII
W9825G6JH-6I
IC SDRAM 256MBIT 54TSOPII
W9864G6JH-6I
IC SDRAM 64MBIT 54TSOPII
WM-5614
CABINET WALL MOUNT 37.25X17.9"
相关代理商/技术参数
W9725G6KB25I TR
制造商:Winbond Electronics Corp 功能描述:256M DDR2-800, X16, IND TEMP
W9725G6KB25K
制造商:WINBOND 制造商全称:Winbond 功能描述:DLL aligns DQ and DQS transitions with clock, Data masks (DM) for write data, Write Data Mask
W9725G6KB-3
制造商:WINBOND 制造商全称:Winbond 功能描述:DLL aligns DQ and DQS transitions with clock, Data masks (DM) for write data, Write Data Mask
W9725G8JB
制造商:WINBOND 制造商全称:Winbond 功能描述:8M ? 4 BANKS ? 8 BIT DDR2 SDRAM
W9725G8JB25
制造商:Winbond Electronics Corp 功能描述:DRAM Chip DDR2 SDRAM 256M-Bit 32Mx8 1.8V 60-Pin WBGA
W9725G8JB25I
制造商:Winbond Electronics Corp 功能描述:DRAM Chip DDR2 SDRAM 256M-Bit 32Mx8 1.8V 60-Pin WBGA
W9725G8JB25ITR
制造商:Winbond Electronics Corp 功能描述:256M DDR2-800, X8, IND TEMP
W9725G8JB25TR
制造商:Winbond Electronics Corp 功能描述:256M DDR2-800, X8