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AS4DDR232M64PBG-38/ET 参数 Datasheet PDF下载

AS4DDR232M64PBG-38/ET图片预览
型号: AS4DDR232M64PBG-38/ET
PDF下载: 下载PDF文件 查看货源
内容描述: 32Mx64 DDR2 SDRAM集成塑封微电路 [32Mx64 DDR2 SDRAM iNTEGRATED Plastic Encapsulated Microcircuit]
分类和应用: 内存集成电路动态存储器双倍数据速率
文件页数/大小: 28 页 / 363 K
品牌: AUSTIN [ AUSTIN SEMICONDUCTOR ]
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iPEM  
2.1 Gb SDRAM-DDR2  
Austin Semiconductor, Inc.  
AS4DDR232M64PBG  
POSTED CAS ADDITIVE LATENCY (AL)  
Posted ꢁAS additive latency (AL) is supported to make the  
command and data bus efficient for sustainable bandwidths  
in DDR2 SDRAM. Bits E3–E5 define the value of AL, as  
shown in Figure 7. Bits E3–E5 allow the user to program  
the DDR2 SDRAM with an inverse AL of 0, 1, 2, 3, or 4  
clocks. Reserved states should not be used as unknown  
operation or incompatibility with future versions may result.  
In this operation, the DDR2 SDRAM allows a READ or WRITE  
command to be issued prior to tRꢁD (MIN) with the  
requirement that AL d” tRꢁD (MIN). A typical application using  
this feature would set AL = tRꢁD (MIN) - 1x tꢁK. The READ or  
WRITE command is held for the time of the AL before it is  
issued internally to the DDR2 SDRAM device. RL is controlled  
by the sum of AL and ꢁL; RL = AL+ꢁL. Write latency (WL) is  
equal to RL minus one clock; WL = AL + ꢁL - 1 x tꢁK.  
FIGURE 8 - EXTENDED MODE REGISTER 2 (EMR2) DEFINITION  
BA1 BA0 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0  
Address Bus  
Extended Mode  
Register (Ex)  
15 14 13 12 11 10  
EMR2  
9
8
7
6
5
4
3
2
1
0
01 01 01  
01 01 01 01 01 01 01 01 01 01 01  
Mode Register Definition  
M15 M14  
High Temperature Self Refresh rate enable  
Commer cial-Temperature default  
Industrial-Temperature option;  
use if TCexceeds 85°C  
E7  
0
0
1
0
1
Mode Register (MR)  
0
0
1
1
Extended Mode Register (EMR)  
Extended Mode Register (EMR2)  
Extended Mode Register (EMR3)  
1
Note: 1. E13 (A13)-E0(A0) are reserved for future use and must be programmed to  
"0." A13 is not used in this device.  
Austin Semiconductor, Inc.  
Austin, Texas 512.339.1188 www.austinsemiconductor.com  
AS4DDR232M64PBG  
Rev. 1.3 6/09  
13  
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