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CYW180-51SXT

更新时间： 2024-02-04 08:26:38

品牌	Logo	应用领域
赛普拉斯 - CYPRESS		晶体时钟发生器微控制器和处理器外围集成电路光电二极管
页数	文件大小	规格书
10页	183K
描述
Peak Reducing EMI Solution

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CYW180-51SXT 技术参数

是否无铅：	不含铅	是否Rohs认证：	符合
生命周期：	Obsolete	零件包装代码：	SOIC
包装说明：	SOP,	针数：	8
Reach Compliance Code：	unknown	ECCN代码：	EAR99
HTS代码：	8542.39.00.01	风险等级：	5.38
Is Samacsys：	N	其他特性：	ALSO OPERATES AT 5V SUPPLY
JESD-30 代码：	R-PDSO-G8	JESD-609代码：	e3
长度：	4.889 mm	湿度敏感等级：	1
端子数量：	8	最高工作温度：	70 °C
最低工作温度：		最大输出时钟频率：	28 MHz
封装主体材料：	PLASTIC/EPOXY	封装代码：	SOP
封装形状：	RECTANGULAR	封装形式：	SMALL OUTLINE
峰值回流温度（摄氏度）：	260	主时钟/晶体标称频率：	28 MHz
认证状态：	Not Qualified	座面最大高度：	1.727 mm
最大供电电压：	3.465 V	最小供电电压：	3.135 V
标称供电电压：	3.3 V	表面贴装：	YES
技术：	CMOS	温度等级：	COMMERCIAL
端子面层：	MATTE TIN	端子形式：	GULL WING
端子节距：	1.27 mm	端子位置：	DUAL
处于峰值回流温度下的最长时间：	30	宽度：	3.8985 mm
uPs/uCs/外围集成电路类型：	CLOCK GENERATOR, OTHER	Base Number Matches：	1

CYW180-51SXT 数据手册

W180

input. The output frequency is then equal to the ratio of P/Q

times the reference frequency. (Note: For the W180 the output

frequency is equal to the input frequency.) The unique feature

of the Spread Spectrum Frequency Timing Generator is that a

modulating waveform is superimposed at the input to the VCO.

This causes the VCO output to be slowly swept across a

predetermined frequency band.

Overview

The W180 products are one series of devices in the Cypress

PREMIS family. The PREMIS family incorporates the latest

advances in PLL spread spectrum frequency synthesizer

techniques. By frequency modulating the output with a

low-frequency carrier, peak EMI is greatly reduced. Use of this

technology allows systems to pass increasingly difficult EMI

testing without resorting to costly shielding or redesign.

Because the modulating frequency is typically 1000 times

slower than the fundamental clock, the spread spectrum

process has little impact on system performance.

In a system, not only is EMI reduced in the various clock lines,

but also in all signals which are synchronized to the clock.

Therefore, the benefits of using this technology increase with

the number of address and data lines in the system. The

Simplified Block Diagram on page 1 shows a simple imple-

mentation.

Frequency Selection With SSFTG

In Spread Spectrum Frequency Timing Generation, EMI

reduction depends on the shape, modulation percentage, and

frequency of the modulating waveform. While the shape and

frequency of the modulating waveform are fixed for a given

frequency, the modulation percentage may be varied.

Functional Description

Using frequency select bits (FS2:1 pins), the frequency range

can be set (see Table 2). Spreading percentage is set with pin

SS% as shown in Table 1.

The W180 uses a phase-locked loop (PLL) to frequency

modulate an input clock. The result is an output clock whose

frequency is slowly swept over a narrow band near the input

signal. The basic circuit topology is shown in Figure 1. The

input reference signal is divided by Q and fed to the phase

detector. A signal from the VCO is divided by P and fed back

to the phase detector also. The PLL will force the frequency of

the VCO output signal to change until the divided output signal

and the divided reference signal match at the phase detector

A larger spreading percentage improves EMI reduction.

However, large spread percentages may either exceed

system maximum frequency ratings or lower the average

frequency to a point where performance is affected. For these

reasons, spreading percentages options are provided.

Clock Input

CLKOUT

Freq.

Divider

Phase

Detector

Charge

Pump

Post

Dividers

Reference Input

(EMI suppressed)

VCO

Modulating

Waveform

Feedback

Divider

PLL

GND

Figure 1. Functional Block Diagram

Document #: 38-07156 Rev. *B

Page 3 of 10

1 234 5 6 7...10

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与CYW180-51SXT相关器件

型号	品牌	描述	获取价格	数据表
CYW180-52SX	CYPRESS	Peak Reducing EMI Solution	获取价格
CYW180-52SXT	CYPRESS	Peak Reducing EMI Solution	获取价格
CYW180-53SX	CYPRESS	Peak Reducing EMI Solution	获取价格
CYW180-53SXT	CYPRESS	Peak Reducing EMI Solution	获取价格
CYW181-01SX	CYPRESS	Peak-Reducing EMI Solution	获取价格
CYW181-01SXT	CYPRESS	Peak-Reducing EMI Solution	获取价格

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