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MX812 参数 Datasheet PDF下载

MX812图片预览
型号: MX812
PDF下载: 下载PDF文件 查看货源
内容描述: VSR CODEC与DRAM控制 [VSR CODEC WITH DRAM CONTROL]
分类和应用: 动态存储器
文件页数/大小: 14 页 / 173 K
品牌: CMLMICRO [ CML MICROCIRCUITS ]
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VSR CODEC with DRAM CONTROL  
5
MX812 PRELIMINARY INFORMATION  
Application Information ......  
+ 5.0V  
+ 5.0V  
VCC  
VDD  
VCC  
VCC  
VDD  
WE  
CAS  
W
WE  
W
W
CAS  
RAS  
A10  
A9  
CAS  
CAS  
RAS  
CAS  
RAS  
RAS1  
RAS1  
A10/R2  
A10/R2  
A9  
A8  
A9  
A8  
A9  
A8  
A9  
A8  
A8  
A7  
A6  
A7  
A7  
A6  
A7  
A6  
A5  
A4  
A7  
4Mbit.  
DRAM  
1Mbit.  
DRAM.  
No.1  
1Mbit.  
DRAM.  
No.2  
MX812  
A6  
A5  
A4  
MX812  
A6  
A5  
A4  
A5  
A4  
A5  
A4  
A3  
A2  
A1  
A0  
A3  
A2  
A3  
A2  
A1  
A0  
A3  
A2  
A1  
A3  
A2  
A1  
A1  
A0  
Q
A0  
Q
A0  
Q
D
DGND  
D
D
D
D
DGND  
VSS  
V
VSS  
SS  
Figure 4 - Example DRAM Connections  
Choice of DRAM Devices  
DRAM devices chosen should be standard 1,048,576 x 1 or 4,194,304 x 1 Dynamic Random Access  
memories, with ‘CAS before RAS’ refresh, and a Row Address access time of 200 nano-seconds or less.  
BANK  
A
'HC00  
SELECT B  
'HC04  
INPUTS  
WE  
CAS  
RAS1  
A10/R2  
A9  
W
W
CAS  
RAS  
A10  
A9  
CAS  
RAS  
A10  
A9  
A8  
A8  
A8  
A7  
A7  
A7  
4Mbit  
DRAM  
No. 1  
4Mbit  
DRAM  
No. 2  
A6  
A6  
A5  
A4  
A6  
A5  
A4  
MX812  
A5  
A4  
A3  
A2  
A1  
A0  
A3  
A2  
A1  
A3  
A2  
A1  
A0  
Q
A0  
Q
D
D
D
Figure 5 - Use of External Elements to Drive Two 4-MBit DRAM Chips  
Driving Two 4-MBit DRAM Sections  
By adding external logic circuitry, the MX812 can be configured  
to drive two 4-MBit DRAM sections. This will have the effect of  
doubling the available storage time. i.e. 4 minutes at 32kbps.  
With reference to the circuitry shown in Figure 5:  
With the Mode Register MS Bit set to “0” the MX812 treats the  
DRAM sections as two 1-Mbit devices. The external logic makes  
each 4-MBit DRAM appear as four 1-MBit banks selected by the  
Bank Select lines ‘A’ and ‘B.’  
Bank Select  
Inputs  
DRAM No 1  
Pages  
0 – 1023  
DRAM No 2  
Pages  
1024 – 2047  
A
B
0
1
0
1
0
0
1
1
© 1997 MXCOM Inc.  
www.mxcom.com Tele: 800 638-5577 910 744-5050 Fax: 910 744-5054  
Doc. # 20480076.003  
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA  
All trademarks and service marks are held by their respective companies.  
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