18 Output, 3.3V SDRAM Buffer for
Desktop PCs with 4 DIMMs
CY2318BNZ
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
•
CA 95134
•
408-943-2600
Document #: 38-07217 Rev. **
Revised December 4, 2001
Features
• One input to 18 output buffer/driver
• Supports up to four SDRAM DIMMs
• Two additional outputs for feedback
• SMBus interface for individual output control
• Low skew outputs (< 200 ps)
• Up to 100 MHz operation for Industrial temperatures
• Up to 133 MHz operation for Commercial temperatures
• Dedicated OE pin for testing
• Space-saving 48-pin SSOP package
• 3.3V operation
Functional Description
The CY2318BNZ is a 3.3V buffer designed to distribute
high-speed clocks in PC applications. The part has 18 outputs,
16 of which can be used to drive up to four SDRAM DIMMs,
and the remaining can be used for external feedback to a PLL.
The device operates at 3.3V and outputs can run up to 100
MHz, thus making it compatible with Pentium II® processors.
The CY2318BNZ can be used in conjunction with the CY2280,
CY2281, CY2282 or similar clock synthesizer for a complete
Pentium II motherboard solution.
The CY2318BNZ also includes an SMBus interface which can
enable or disable each output clock. On power-up, all output
clocks are enabled (internal pull up). A separate Output Enable
pin facilitates testing on ATE.
Pentium II is a registered trademark of Intel Corporation.
Block Diagram
SMBus
BUF_IN
SDATA
SCLOCK
SDRAM0
SDRAM1
SDRAM2
SDRAM3
SDRAM4
SDRAM5
SDRAM6
SDRAM7
1
2
3
4
NC
NC
VDD
SDRAM15
SDRAM14
VSS
VDD
SDRAM13
SSOP
Top View
Pin Configuration
Decoding
8
5
6
7
12
9
10
11
13
14
15
16
20
17
18
19
24
21
22
23
48
47
46
45
41
44
43
42
37
40
39
38
36
35
34
33
29
32
31
30
25
28
27
26
SDRAM12
VSS
OE
VDD
SDRAM11
SDRAM10
VSS
VDD
SDRAM9
SDRAM8
VSS
VDD
SDRAM17
VSS
VSSIIC
SCLOCK
NC
NC
VDD
SDRAM0
SDRAM1
VSS
VDD
SDRAM2
VSS
BUF_IN
VDD
SDRAM4
SDRAM5
VSS
VDD
SDRAM6
SDRAM7
VSS
VDD
SDRAM16
VSS
VDDIIC
SDATA
SDRAM3
SDRAM8
SDRAM9
SDRAM10
SDRAM11
SDRAM12
SDRAM13
SDRAM14
SDRAM15
SDRAM16
SDRAM17
OE
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