Datasheet > CY2254A

CY2254A

更新时间： 2024-11-17 04:37:55

品牌	Logo	应用领域
SPECTRALINEAR		驱动器时钟
页数	文件大小	规格书
7页	111K
描述
Pentium㈢ Processor Compatible Clock Synthesizer/Driver

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中文翻译

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数据手册

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CY2254A 数据手册

Y2254A

CY2254A

Pentium^®Processor Compatible Clock Synthesizer/Driver

• Freq. stability = 0.01% (max.)

Features

• Output duty cycle 45% min. to 55% max.

• Multiple clock outputs to meet requirements of most

Pentium^®motherboards

• Test mode support (ꢀ1 option only)

• 3.3V or 5.0V operation

— Four pin-selectable CPU clocks @ 66.66 MHz, 60.0

MHz, and50.0MHzforsupportof IntelTriton^™PCIset

based PC

• Internal pull-up resistors on S0, S1, and OE inputs

Functional Description

— 55.0 MHz pin-selectable CPU clock also available (ꢀ2

option only)

The CY2254A is a Clock Synthesizer/Driver that provides the

multiple clocks required for a Pentium-based PC. The

CY2254A has low-skew outputs (< 250 ps between the CPU

Clocks, < 250 ps between the PCI Clocks). In addition, the

CY2254A CPU clock outputs have less than 200 ps

cycle-to-cycle jitter. Finally, both the PCI and CPU clock

outputs meet the 1 V/ns slew rate requirement of a Pentium

processor-based system.

— Six PCI clocks at 1/2 CPU Clock frequency

— One I/O clock @ 24 MHz

— OneKeyboardController clock@ 12MHz (ꢀ1option)

or one Universal Serial Bus clock @ 48 MHz

(ꢀ2 option)

— Two Ref. clocks @ 14.318 MHz

— Ref. 14.318 MHz Xtal oscillator input

• CPU clock jitter < 200 ps cycle-to-cycle

• Low skew outputs

The CY2254A accepts a 14.318 MHz reference signal as its

input. The CY2254A has 2 PLLs, one of which generates the

CPU and PCI clocks, and the other generates the I/O and

Keyboard Controller or USB clocks. The CY2254A runs off

either a 3.3V or 5V supply.

— < 250 ps between CPU clocks

The CY2254A is available in two options. The ꢀ1 option

supports the Intel Triton PCIset and provides a 12 MHz

keyboard clock on pin 25. The ꢀ2 option provides a 48 MHz

USB clock on pin 25 and supports the Cyrix^®M1 processor.

— < 250 ps between PCI clocks

— < 500 ps between CPU and PCI clocks (ꢀ2 option)

— CPU clock leads PCI clock by +1 ns min. to +4 ns

max. (ꢀ1 option)

Pin Configuration

Logic Block Diagram

REF0 (14.318 MHz)

Top View

REF1 (14.318 MHz)

KBDCLK (12 MHz)

SOIC

SYS

PLL

REF0

REF1

14.318

MHz

OSC.

XTALIN

IOCLK (24 MHz)

XTALOUT

USBCLK (48 MHz)

XTALOUT

SEEBELOW

IOCLK

CPUCLK0

CPUCLK1

CPU

PLL

CPUCLK0

CPUCLK1

CPUCLK2

CPUCLK3

PCICLK2

PCICLK3

ROM

CPUCLK2

CPUCLK3

PCICLK4

PCICLK5

DELAY

PCICLK1

PCICLK0

ꢀ1 option only

PCICLK0

PCICLK1

PCICLK2

PCICLK3

PIN 25

OPTION

KBDCLK

12 MHz

USBCLK

48 MHz

ꢀ1

ꢀ2

PCICLK4

PCICLK5

Rev 1.0, November 25, 2006

2200 Laurelwood Road, Santa Clara, CA 95054

Page 1 of 7

www.SpectraLinear.com

Tel:(408) 855-0555 Fax:(408) 855-0550

12 3 4 5 6 7

中文翻译

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与CY2254A相关器件

型号	品牌	获取价格	描述	数据表
CY2254ASC-1	SPECTRALINEAR	获取价格	Pentium㈢ Processor Compatible Clock Synthesiz
CY2254ASC-1	CYPRESS	获取价格	Pentium Processor Compatible Clock Synthesizer/Driver
CY2254ASC-1T	CYPRESS	获取价格	Processor Specific Clock Generator, 66.66MHz, MOS, PDSO28, 0.300 INCH, PLASTIC, SOIC-28
CY2254ASC-2	CYPRESS	获取价格	Pentium Processor Compatible Clock Synthesizer/Driver
CY2254ASC-2	SPECTRALINEAR	获取价格	Pentium㈢ Processor Compatible Clock Synthesiz
CY2254ASC-2T	CYPRESS	获取价格	暂无描述
CY2255	ETC	获取价格	CPU System Clock Generator
CY2256PVC-1	ETC	获取价格	CPU System Clock Generator
CY2256SC-1	ETC	获取价格	CPU System Clock Generator
CY2257	ETC	获取价格	CPU System Clock Generator

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