100-MHz Spread Spectrum Clock Synthesizer/Driver with
USB, Hublink, and SDRAM Support
CY2287
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
•
CA 95134
•
408-943-2600
June 23, 1999
Features
Benefits
• Mixed 2.5V and 3.3V Operation
Usable with Pentium
II, K6, and 6x86 Processors
• Multiple output clocks at different frequencies
— Three CPU clocks at 2.5V, up to 100 MHz
— Nine 3.3V SDRAM clocks at 100 MHz
— Eight synchronous PCI clocks at 33 MHz
— Two synchronous APIC clocks at 16.67 MHz or 33
MHz
— Two 3V66 clocks at 66 MHz
— Two USB clocks at 48 MHz
— One reference clock at 14.318 MHz
Single-chip main motherboard clock generator
— High-Speed Processor Support
— Supports Two 4-Clock SDRAM DIMMs
— Support for Six PCI Slots
— Synchronous to the CPU Clock
— Hublink Support
— Universal Serial Bus Support
— Also used as an input strap to determine APIC frequency
• Spread Spectrum clocking
— 31 kHz modulation frequency
— EPROM programmable percentage of spreading
— Default is –0.6%, which is recommended by Intel®
— Additional options of –0.25% and –0.4% available
Enables reduction of EMI
• Power-down features
Supports mobile systems
•I2C™ Interface
Dynamic output control
• Low skew and low jitter outputs
Meets tight system timing requirements at high frequency
• Test Mode
Enables ATE and “bed of nails” testing
• 56-pin SSOP package
Widely available, standard package enables lower cost
Intel and Pentium are registered trademarks of Intel Corporation.
I2C is a trademark of Philips Corporation.
SERIAL INTERFACE
CONTROL LOGIC
Logic Block Diagram
EPROM
XTALOUT
XTALIN
APIC [0–1] (16.67/33MHz)
14.318
MHz
OSC.
SDRAM [0-8] (100 MHz)
SEL1
CPU
PLL
REF0/SEL33 (14.318 MHz)
CPU [0–2] (66/100 MHz)
PCI [0–7] (33MHz)
SYS
PLL
USB [0–1] (48MHz)
EPROM
Configurable
Logic
PWR_DWN
3V66 [0–1] (66MHz)
SSOP
Top View
1
2
3
4
5
6
7
8
9
10
11
12
33
32
31
30
29
36
35
REF0/SEL33
34
13
14
15
16
17
18
19
20
21
22
23
24
45
44
43
42
41
37
38
39
40
48
47
46
VDDREF
XTAL_IN
XTAL_OUT
25
26
27
28
49
52
51
50
53
56
55
54
VDDPCI
VSSPCI
AVSS
SCLK
SDRAM8
SDRAM4
VSSSDRAM
VDDAPIC
3V66_0
PCI3
PCI7
USB1
SDRAM6
SDRAM2
CPU1
VSSAPIC
VSSREF
VSS3V66
3V66_1
VDD3V66
PCI0
PCI1
PCI2
VSSPCI
PCI4
PCI5
PCI6
VDDPCI
AVDD
VSSUSB
USB0
VDDSDRAM
PWRDWN
VSSSDRAM
SDRAM7
VDDSDRAM
SDRAM5
VSSSDRAM
SDRAM3
VDDSDRAM
SDRAM1
SDRAM0
VSSCPU
CPU2
VDDCPU
CPU0
APIC1
APIC0
VDDUSB
SEL0
SDATA
SEL1
SCLK
SDATA
SEL0
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