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W3H64M72E-ESC 参数 Datasheet PDF下载

W3H64M72E-ESC图片预览
型号: W3H64M72E-ESC
PDF下载: 下载PDF文件 查看货源
内容描述: 64M X 72 DDR2 SDRAM 208 PBGA多芯片封装 [64M x 72 DDR2 SDRAM 208 PBGA Multi-Chip Package]
分类和应用: 存储内存集成电路动态存储器双倍数据速率
文件页数/大小: 30 页 / 942 K
品牌: WEDC [ WHITE ELECTRONIC DESIGNS CORPORATION ]
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W3H64M72E-XSBX  
White Electronic Designs  
ADVANCED*  
DLL RESET  
TABLE 2 – BURST DEFINITION  
DTT RESEꢀ is defined by bit M8, as shown in Figure 5.  
Programming bit M8 to “1” will activate the DTT RESEꢀ  
function. Bit M8 is self-clearing, meaning it returns back  
to a value of “0” after the DTT RESEꢀ function has been  
issued.  
Order of Accesses Within a Burst  
Type = Sequential Type = Interleaved  
Burst  
Starting Column  
Address  
Length  
A1  
0
A0  
0
0-1-2-3  
1-2-3-0  
2-3-0-1  
3-0-1-2  
0-1-2-3  
1-0-3-2  
2-3-0-1  
3-2-1-0  
Anytime the DTTRESEꢀ function is used, 200 clock cycles  
must occur before a READ command can be issued to  
allow time for the internal clock to be synchronized with  
the external clock. Failing to wait for synchronization  
4
0
1
1
0
1
1
t
t
A2  
0
A1  
0
A0  
0
to occur may result in a violation of the AC or DQSCK  
parameters.  
0-1-2-3-4-5-6-7  
1-2-3-0-5-6-7-4  
2-3-0-1-6-7-4-5  
3-0-1-2-7-4-5-6  
4-5-6-7-0-1-2-3  
5-6-7-4-1-2-3-0  
6-7-4-5-2-3-0-1  
7-4-5-6-3-0-1-2  
0-1-2-3-4-5-6-7  
1-0-3-2-5-4-7-6  
2-3-0-1-6-7-4-5  
3-2-1-0-7-6-5-4  
4-5-6-7-0-1-2-3  
5-4-7-6-1-0-3-2  
6-7-4-5-2-3-0-1  
7-6-5-4-3-2-1-0  
0
0
1
WRITE RECOVERY  
0
1
0
Write recovery (WR) time is defined by bits M9–M11, as  
shown in Figure 5. ꢀhe WR register is used by the DDR2  
SDRAM during WRIꢀE with auto precharge operation.  
During WRIꢀE with auto precharge operation, the DDR2  
SDRAM delays the internal auto precharge operation by  
WR clocks (programmed in bits M9–M11) from the last  
data burst.  
8
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
WR values of 2, 3, 4, 5, or 6 clocks may be used for  
programming bits M9–M11. ꢀhe user is required to  
program the value of WR, which is calculated by dividing  
tWR (in ns) by tCK (in ns) and rounding up a non integer  
value to the next integer; WR [cycles] = tWR [ns] / tCK [ns].  
Reserved states should not be used as unknown operation  
or incompatibility with future versions may result.  
NOTES:  
1. For a burst length of two, A1-Ai select two-data-element block; A0 selects the  
starting column within the block.  
2. For a burst length of four, A2-Ai select four-data-element block; A0-1 select the  
starting column within the block.  
3. For a burst length of eight, A3-Ai select eight-data-element block; A0-2 select the  
starting column within the block.  
4. Whenever a boundary of the block is reached within a given sequence above, the  
following access wraps within the block.  
POWER-DOWN MODE  
Active power-down (PD) mode is defined by bit M12,  
as shown in Figure 5. PD mode allows the user to  
determine the active power-down mode, which determines  
performance versus power savings. PD mode bit M12 does  
not apply to precharge PD mode.  
OPERATING MODE  
ꢀhe normal operating mode is selected by issuing a  
command with bit M7 set to “0,” and all other bits set to  
the desired values, as shown in Figure 5. When bit M7 is  
“1,” no other bits of the mode register are programmed.  
Programming bit M7 to “1” places the DDR2 SDRAM into a  
test mode that is only used by the manufacturer and should  
not be used. No operation or functionality is guaranteed  
if M7 bit is ‘1.’  
When bit M12 = 0, standard active PD mode or “fast-exit”  
active PD mode is enabled. ꢀhe tXARD parameter is used  
for fast-exit active PD exit timing. ꢀhe DTT is expected to  
be enabled and running during this mode.  
When bit M12 = 1, a lower-power active PD mode or “slow-  
exit” active PD mode is enabled. ꢀhe tXARD parameter is  
used for slow-exit active PD exit timing. ꢀhe DTT can be  
enabled, but “frozen” during active PD mode since the exit-  
to-READ command timing is relaxed. ꢀhe power difference  
expected between PD normal and PD low-power mode is  
defined in the ICC table.  
White Electronic Designs Corp. reserves the right to change products or specifications without notice.  
March 2006  
Rev. 1  
10  
White Electronic Designs Corporation • (602) 437-1520 • www.wedc.com