IDT72T6480 Integrated Device Technology, IDT72T6480 Datasheet - Page 12

• Manufacturer Part Number: IDT72T6480
• Description: X48 Sequential Flow-control Device Up To 1gigabit
• Manufacturer: Integrated Device Technology

EXTERNAL MEMORY CONFIGURATIONS
a 64-bit output data bus that provides up to four (16-bit SDRAM) external DDR
SDRAM connections. For multiple memory connections, they must be of the
same density configuration and speed grade. For example, two device
connected cannot consist of one 128Mb and one 256Mb memory nor two
128Mb with one at 100MHz and the other at 133MHz. Below is a summary of
the possible configurations:
TABLE 3 – TOTAL POSSIBLE EXTERNAL MEMORY CONFIGURATIONS
NOTES:
1. The chip solution number includes the sequential flow-control device and external DDR SDRAM
2. See Figure 2a-2g for the 7 different configurations referenced in the table above.
IDT72T6480 2.5V, SEQUENTIAL FLOW-CONTROL DEVICE
x12, x24, x48 BIT WIDE CONFIGURATION
The DDR SDRAM interface of the sequential flow-control (SFC) device has
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One 16-bit device connecting a x16 interface to the DDR SDRAM
One 32-bit device connecting a x32 interface to the DDR SDRAM
Two Chip Solution
1 x 256Mb [16M x 16]
Total memory: 128Mb
Total memory: 256Mb
Total memory: 128Mb
Total memory: 256Mb
1 x 256Mb [8M x 32]
1 x 128Mb [8M x 16]
1 x128Mb [4M x 32]
(2)
Configuration 1, 2
(1)
Three Chip Solution
(2)
2 x 256Mb [16M x 16]
Total memory: 256Mb
Total memory: 512Mb
Total memory: 256Mb
Total memory: 512Mb
2 x 128Mb [4M x 32]
2 x 256Mb [8M x 32]
2 x 128Mb [8M x 16]
Configurations 3, 4, 5
(1)
Four Chip Solution
3 x 256Mb [16M x 16]
Total memory: 768Mb
Total memory: 384Mb
3 x 128Mb [8M x 16]
(2)
Configuration 6
N/A
N/A
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device. The storage density can range from a minimum of 128Mb to a maximum
of 1Gb. Table 3 lists the possible ways to connect the DDR SDRAMs and the
number of chipset solutions to obtain the various storage densities.
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•
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These various configurations determine the storage density of the SFC
Two 16-bit devices connecting a x32 interface to the DDR SDRAM
Two 32-bit devices connecting a x36 interface to the DDR SDRAM
Two 32-bit devices connecting a x64 interface to the DDR SDRAM
Three 16-bit devices connecting a x36 interface to the DDR SDRAM
Four 16-bit devices connecting a x64 interface to the DDR SDRAM
(1)
Five Chip Solution
4 x 256Mb [16M x 16]
Total memory: 512Mb
4 x 128Mb [8M x 16]
Total memory: 1Gb
(2)
Configuration 7
N/A
N/A
(1)
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
OCTOBER 10, 2005