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参数资料
| 型号： | CY2285PVC-2 |
| 厂商： | CYPRESS SEMICONDUCTOR CORP |
| 元件分类： | XO, clock |
| 英文描述： | 100-MHz Pentium㈢II Clock Synthesizer/Driver with Spread Spectrum for Mobile PCs |
| 中文描述： | 100 MHz, PROC SPECIFIC CLOCK GENERATOR, PDSO28 |
| 封装： | 0.210 INCH, SSOP-28 |
| 文件页数： | 1/9页 |
| 文件大小： | 132K |
| 代理商： | CY2285PVC-2 |
100-MHz Pentium
II Clock Synthesizer/Driver
with Spread Spectrum for Mobile PCs
The CY2285 possesses power-down, CPU stop, and PCI stop
pins for power management control. The signals are synchro-
nized on-chip, and ensure glitch-free transitions on the out-
puts. When the CPU_STOP input is asserted, the CPU clock
outputs are driven LOW. When the PCI_STOP input is assert-
ed, the PCI clock outputs (except the free-running PCI clock)
are driven LOW. When the PWR_DWN pin is asserted, the
reference oscillator and PLLs are shut down, and all outputs
are driven LOW.
The CY2285-2 features an early PCI clock which leads the
other PCI clocks by 1–4 ns. The CY2285-2 also features a
DIV4 pin which allows for dynamic shifting of CPU and PCI
clocks from the default frequency to the default/4.
CY2285 Selector Guide
CY2285
Cypress Semiconductor Corporation
3901 North First Street
San Jose
CA 95134
408-943-2600
May 18, 2000
Features
Mixed 2.5V and 3.3V operation
Complete clock solution for Pentium II, and other sim-
ilar processor-based motherboards
—Two CPU clocks at 2.5V up to 100 MHz
—Six synchronous PCI clocks, one free-running
—Two 3.3V Reference clocks at 14.318 MHz
—One 3.3V USB clock running at 48 MHz
—One 3.3V USB/IO clock running at 48 MHz/24 MHz
Spread Spectrum clocking for EMI control
1.5–4.0 ns delay between CPU and PCI clocks
Power-down, CPU stop and PCI stop pins
Low skew outputs,
≤
175 ps between CPU clocks
Early PCI clock leads PCI by 1–4 ns (-2 option)
DIV4 allows dynamic shifting of CPU and PCI clocks
from the default frequency to default/4 (-2 option)
Factory-EPROM programmable output drive and slew
rate for EMI customization
Available in space-saving 28-pin SSOP package
Functional Description
The CY2285 is a clock synthesizer/driver for Pentium II, or
other similar processor-based mobile PCs requiring up to
100-MHz support. The CY2285 outputs two CPU clocks at
2.5V. There are six PCI clocks, running at one-half or one-third
the CPU clock frequency of 66.6 MHz and 100 MHz respec-
tively. One of the PCI clocks is free-running. Additionally, the
part outputs two 3.3V reference clocks at 14.318 MHz.
The CY2285 provides incorporates the Intel-defined spread
spectrum features. It provides a –0.6% downspread on the
CPU and PCI clocks, which can help reduce EMI in certain
high-speed systems.
Notes:
1.
2.
One free-running PCI clock.
One early PCI clock.
Clock Outputs
CY2285-1
CY2285-2
CY2285-3
CPU (66,
100 MHz)
2
2
2
PCI (CPU/2,
CPU/3 MHz)
6
[1]
7
[1, 2]
6
[1]
Ref. (14.318 MHz)
2
2
1
USB (48 MHz)
1
1
1
USB/IO (48
MHz/24 MHz se-
lectable)
1
N/A
1
CPU-PCI delay
1.5–4.0 ns
1.5–4.0 ns
1.5–4.0 ns
EPCI-PCI delay
N/A
1.0–4.0 ns
N/A
Spread Spectrum
–0.6%
Downspread
–0.6%
Downspread
–0.6%
Downspread
Intel and Pentium are registered trademarks of Intel Corporation.
Logic Block Diagram
EPROM
XTALOUT
XTALIN
14.318
MHz
CPU
PLL
Delay
REF1/SEL48
REF1 (-2,-3 option)
CPUCLK [0–1]
V
DDCPU
PCICLK [1-5]
EPCICLK (-2 option)
STOP
LOGIC
STOP
LOGIC
CPU_STOP
DIV4
Divider
PCI_STOP
V
DDPCI
PCICLK_F
V
DDPCI
V
DDREF
REF0/SPREAD
REF0 (-2 option)
SYS
PLL
USBCLK
V
DD48
USB_IOCLK/TS (-1 option)
USBCLK/SEL100/66 (-2 option)
V
DD48
V
DDPCI
PWR_DWN
/4
SPREAD (-2,-3 option)
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| CY2287PVC-1 | 100-MHz Spread Spectrum Clock Synthesizer/Driver with USB, Hublink, and SDRAM Support |
| CY22K7 | 133-MHz Spread Spectrum Clock Generator For Use With the AMD-K7 Processor and AMD-750 Chipset |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| CY2285PVC-3 | 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:100-MHz Pentium㈢II Clock Synthesizer/Driver with Spread Spectrum for Mobile PCs |
| CY2287 | 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:100-MHz Spread Spectrum Clock Synthesizer/Driver with USB, Hublink, and SDRAM Support |
| CY2287-1 | 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:100-MHz Spread Spectrum Clock Synthesizer/Driver with USB, Hublink, and SDRAM Support |
| CY2287PVC-1 | 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:100-MHz Spread Spectrum Clock Synthesizer/Driver with USB, Hublink, and SDRAM Support |
| CY2291 | 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:Three-PLL General Purpose EPROM Programmable Clock Generator |
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