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參數(shù)資料
| 型號： | W3E64M72S-266BI |
| 廠商： | WHITE ELECTRONIC DESIGNS CORP |
| 元件分類： | DRAM |
| 英文描述： | 64M X 72 SYNCHRONOUS DRAM, 0.75 ns, PBGA219 |
| 封裝： | 25 X 32 MM, PLASTIC, BGA-219 |
| 文件頁數(shù)： | 19/19頁 |
| 文件大小： | 674K |
| 代理商： | W3E64M72S-266BI |
W3E64M72S-XBX
9
White Electronic Designs Corporation (602) 437-1520 www.wedc.com
White Electronic Designs
June 2005
Rev. 0
ADVANCED
White Electronic Designs Corp. reserves the right to change products or specications without notice.
COMMAND
READ
NOP
CL = 2.5
DON'T CARE
TRANSITIONING DATA
DQ
DQS
T0
T1
T2
T2n
T3
T3n
COMMAND
READ
NOP
CL = 2
DQ
DQS
CLK
CLK#
T0
T1
T2
T2n
T3
T3n
Burst Length = 4 in the cases shown
Shown with nominal tAC and nominal tDSDQ
DATA
CLK
CLK#
FIGURE 4 – CAS LATENCY
FIGURE 5 – EXTENDED MODE REGISTER
DEFINITION
DLL
Enable
Disable
A9
A7
A6
A5
A4
A3
A8
A2
A1
A0
Extended Mode
Register (Ex)
Address Bus
A10
A11
11
01
BA0
BA1
E0
0
1
Drive Strength
Normal
Reserved
E1
0
1
Operating Mode
Reserved
E1, E0
Valid
-
E12
0
-
E10
0
-
E9
0
-
E8
0
-
E7
0
-
E6
0
-
E5
0
-
E4
0
-
E3
0
-
A12
E11
0
-
1. E14 and E13 must be "0, 1" to select the Extended Mode Register (vs. the base Mode Register)
2. The QFC# function is not supported.
E2
0
-
14 13 12 11 10
9
8
76543210
DLL
DS
Operating Mode
during an AUTO REFRESH command. Each DDR SDRAM
requires AUTO REFRESH cycles at an average interval
of 7.8125s (maximum).
To allow for improved efficiency in scheduling and
switching between tasks, some exibility in the absolute
refresh interval is provided. A maximum of eight AUTO
REFRESH commands can be posted to any given DDR
SDRAM, meaning that the maximum absolute interval
between any AUTO REFRESH command and the next
AUTO REFRESH command is 9 x 7.8125s (70.3s). This
maximum absolute interval is to allow future support for
DLL updates internal to the DDR SDRAM to be restricted
to AUTO REFRESH cycles, without allowing excessive
drift in tAC between updates.
Although not a JEDEC requirement, to provide for future
functionality features, CKE must be active (High) during
the AUTO REFRESH period. The AUTO REFRESH period
begins when the AUTO REFRESH command is registered
and ends tRFC later.
SELF REFRESH*
The SELF REFRESH command can be used to retain
data in the DDR SDRAM, even if the rest of the system is
powered down. When in the self refresh mode, the DDR
SDRAM retains data without external clocking. The SELF
REFRESH command is initiated like an AUTO REFRESH
command except CKE is disabled (LOW). The DLL is
automatically disabled upon entering SELF REFRESH and
is automatically enabled upon exiting SELF REFRESH (A
DLL reset and 200 clock cycles must then occur before a
READ command can be issued). Input signals except CKE
are “Don’t Care” during SELF REFRESH. VREF voltage is
also required for the full duration of SELF REFRESH.
The procedure for exiting self refresh requires a sequence
of commands. First, CK and CK# must be stable prior
to CKE going back HIGH. Once CKE is HIGH, the DDR
SDRAM must have NOP commands issued for tXSNR,
because time is required for the completion of any internal
refresh in progress.
A simple algorithm for meeting both refresh and DLL
requirements is to apply NOPs for tXSNR time, then a DLL
Reset and NOPs for 200 additional clock cycles before
applying any other command.
* Self refresh available in commercial and industrial temperatures only.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| W3E64M72S-266BM | 制造商:WEDC 制造商全稱:White Electronic Designs Corporation 功能描述:64Mx72 DDR SDRAM |
| W3E64M72S-266ESC | 制造商:WEDC 制造商全稱:White Electronic Designs Corporation 功能描述:64Mx72 DDR SDRAM |
| W3E64M72S-266ESI | 制造商:WEDC 制造商全稱:White Electronic Designs Corporation 功能描述:64Mx72 DDR SDRAM |
| W3E64M72S-266ESM | 制造商:WEDC 制造商全稱:White Electronic Designs Corporation 功能描述:64Mx72 DDR SDRAM |
| W3E64M72S-266SBC | 制造商:Microsemi Corporation 功能描述:64M X 72 DDR, 2.5V, 266 MHZ, 219 PBGA, COMMERCIAL TEMP. - Bulk |
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