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CY2280PVC-11S 参数 Datasheet PDF下载

CY2280PVC-11S图片预览
型号: CY2280PVC-11S
PDF下载: 下载PDF文件 查看货源
内容描述: 100 - MHz奔腾II时钟合成器/驱动器,具有扩频移动或台式电脑 [100-MHz Pentium II Clock Synthesizer/Driver with Spread Spectrum for Mobile or Desktop PCs]
分类和应用: 晶体驱动器时钟发生器微控制器和处理器外围集成电路光电二极管电脑PC
文件页数/大小: 12 页 / 155 K
品牌: CYPRESS [ CYPRESS SEMICONDUCTOR ]
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CY2280
100-MHz Pentium
®
II Clock Synthesizer/Driver with
Spread Spectrum for Mobile or Desktop PCs
Features
• Mixed 2.5V and 3.3V operation
• Clock solution for Pentium® II, and other similar pro-
cessor-based motherboards
— Four 2.5V CPU clocks up to 100 MHz
— Eight 3.3V sync. PCI clocks, one free-running
— Two 3.3V 48-MHz USB clocks
— Three 3.3V Ref. clocks at 14.318 MHz
— Two 2.5V APIC clocks at 14.318 MHz or PCI/2
• EMI control
— Spread spectrum clocking
— Factory-EPROM programmable spread spectrum
margin
Factory-EPROM programmable output drive and
slew rate
• Factory-EPROM programmable CPU clock frequencies
for custom configurations
• Available in space-saving 48-pin SSOP package
Functional Description
The CY2280 is a Spread Spectrum clock synthesizer/driver for
a Pentium II, or other similar processor-based PC requiring
100-MHz support. All of the required system clocks are provid-
ed in a space-saving 48-pin SSOP package. The CY2280 can
be used with the CY231x for a total solution for systems with
SDRAM.
The CY2280 provides the option of spread spectrum clocking
on the CPU and PCI clocks for reduced EMI. A downspread
percentage is introduced when the SEL_SS input is asserted.
The device can be run without spread spectrum when the
SEL_SS input is deasserted. The percentage of spreading is
EPROM-programmable to optimize EMI-reduction.
The CY2280 has power-down, CPU stop, and PCI stop pins
for power management control. The signals are synchronized
on-chip, and ensure glitch-free transitions on the outputs.
When the CPU_STOP input is asserted, the CPU clock out-
puts are driven LOW. When the PCI_STOP input is asserted,
the PCI clock outputs (except the free-running PCI clock) are
driven LOW. When the PWR_DWN pin is asserted, the refer-
ence oscillator and PLLs are shut down, and all outputs are
driven LOW.
CY2280 Selector Guide
CY2280 Configuration Options
Clock Outputs
CPU (66.6, 100 MHz)
PCI (CPU/2, CPU/3)
USB (48 MHz)
APIC (14.318 MHz)
APIC (PCI/2)
Reference (14.318 MHz)
CPU-PCI delay
CPU-APIC delay
Spread Spectrum (Downspread)
–1
4
8
2
2
3
1.5−4.0 ns
N/A
-1
-2
CPU_STOP
XTALIN
XTALOUT
14.318
MHz
OSC.
CPU
PLL
Divider
STOP
LOGIC
–11S
4
8
2
2
3
1.5−4.0 ns
−0.6%
APIC [0:1]
V
DDAPIC
REF [0-2]
V
DDREF
CPUCLK [0-3]
V
DDCPU
PCICLK_F
–21S
4
8
2
2
3
1.5−4.0 ns
2.0–4.5 ns
−0.6%
Logic Block Diagram
PWR_DWN
SEL0
SEL1
SEL100
SEL_SS
PCI_STOP
SYS PLL
Delay
STOP
LOGIC
EPROM
V
DDPCI
PCI [1-7]
V
DDPCI
USBCLK [0:1]
V
DDUSB
Pentium is a registered trademark of Intel Corporation.
Cypress Semiconductor Corporation
Document #: 38-07207 Rev. *A
3901 North First Street
San Jose
CA 95134 • 408-943-2600
Revised December 08, 2002