Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.NET

X  

Preview PDF Download HTML

W9725G6KB25A Datasheet(HTML) 9 Page - Winbond

Part No. W9725G6KB25A
Description  DLL aligns DQ and DQS transitions with clock, Data masks (DM) for write data, Write Data Mask
Download  87 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  WINBOND [Winbond]
Homepage  http://www.winbond.com
Logo 

W9725G6KB25A Datasheet(HTML) 9 Page - Winbond

Back Button W9725G6KB25A Datasheet HTML 9Page - Winbond Next Button
Zoom Inzoom in Zoom Outzoom out
Go To Page :
/ 87 page
background image
W9725G6KB
Publication Release Date: Sep. 03, 2012
- 9 -
Revision A03
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 × VDDQ 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 VDD voltage ramp time must be no greater than 200 mS from when VDD ramps from 300
mV to VDD min; and during the VDD voltage ramp, |VDD -VDDQ|
0.3 volts.
VDD, VDDL and VDDQ are driven from a single power converter output
VTT is limited to 0.95V max
VREF
*2 tracks VDDQ/2
VDDQ
VREF must be met at all times
B. Voltage levels at I/Os and outputs must be less than VDDQ during voltage ramp time to avoid
DRAM latch-up. During the ramping of the supply voltages, VDD
VDDL VDDQ must be
maintained and is applicable to both AC and DC levels until the ramping of the supply voltages
is complete.
Apply VDD/VDDL
*3 before or at the same time as VDDQ
Apply VDDQ
*4 before or at the same time as VTT
VREF
*2 tracks VDDQ/2
VDDQ
VREF must be met at all times.
Apply VTT
The VTT voltage ramp time from when VDDQ min is achieved on VDDQ to when VTT min is
achieved on VTT 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.


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59  60  61  62  63  64  65  66  67  68  69  70  71  72  73  74  75  76  77  78  79  80  81  82  83  84  85  86  87 


Datasheet Download

Go To PDF Page


Link URL



Privacy Policy
ALLDATASHEET.NET
Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Bookmark   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn