参数资料
型号: W158H
厂商: Silicon Laboratories Inc
文件页数: 6/12页
文件大小: 0K
描述: IC CLOCK CK98 SSCG CK98 56SSOP
标准包装: 26
类型: *
PLL: 带旁路
输入: 晶体
输出: 时钟
电路数: 1
比率 - 输入:输出: 1:24
差分 - 输入:输出: 无/无
频率 - 最大: 133MHz
除法器/乘法器: 是/无
电源电压: 2.375 V ~ 3.465 V
工作温度: 0°C ~ 70°C
安装类型: *
封装/外壳: *
供应商设备封装: *
包装: *
W158
..... Document #: 38-07164 Rev. *A Page Page 3 of 12 of 12
Spread Spectrum Clocking
The device generates a clock that is frequency modulated in
order to increase the bandwidth that it occupies. By increasing
the bandwidth of the fundamental and its harmonics, the ampli-
tudes of the radiated electromagnetic emissions are reduced.
This effect is depicted in Figure 1.
As shown in Figure 1, a harmonic of a modulated clock has a
much lower amplitude than that of an unmodulated signal. The
reduction in amplitude is dependent on the harmonic number
and the frequency deviation or spread. The equation for the
reduction is:
dB = 6.5 + 9*log10(P) + 9*log10(F)
Where P is the percentage of deviation and F is the frequency
in MHz where the reduction is measured.
The output clock is modulated with a waveform depicted in
Figure 2. This waveform, as discussed in “Spread Spectrum
Clock Generation for the Reduction of Radiated Emissions” by
Bush, Fessler, and Hardin produces the maximum reduction
in the amplitude of radiated electromagnetic emissions. The
deviation selected for this chip is –0.5% downspread. Figure
2 details the Cypress spreading pattern. Cypress does offer
options with more spread and greater EMI reduction. Contact
your local Sales representative for details on these devices.
Figure 1. Clock Harmonic with and without SSCG Modulation Frequency Domain Representation
100%
60%
20%
80%
40%
0%
–20%
–40%
–60%
–80%
–100%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Time
Fr
equ
e
ncy
Sh
if
t
Figure 2. Modulation Waveform Profile
相关PDF资料
PDF描述
W320-04H IC CLK/DRVR CPUOUT 200MHZ 56SSOP
W681511S IC VOICEBAND CODEC 5V 1CH 20SOP
X98014L128-3.3-Z IC VIDEO DIGITIZER TRPL 128MQFP
X98017L128-3.3-Z IC VIDEO DIGITIZER TRPL 128MQFP
X98021L128-3.3-Z IC TRPL VID DIGITIZER 128MQFP
相关代理商/技术参数
参数描述
W158HT 功能描述:时钟合成器/抖动清除器 IntelR CK98 Sprd Spectrum Sys Clk Srv RoHS:否 制造商:Skyworks Solutions, Inc. 输出端数量: 输出电平: 最大输出频率: 输入电平: 最大输入频率:6.1 GHz 电源电压-最大:3.3 V 电源电压-最小:2.7 V 封装 / 箱体:TSSOP-28 封装:Reel
W158HVX1 制造商:Magnecraft 功能描述:3-5 Days
W158HVX-1 制造商:Struthers-Dunn 功能描述:Relay;E-Mech;High Voltage;SPDT;Cur-Rtg 200mA;Ctrl-V 24DC;Vol-Rtg 5000DC 制造商:Struthers-Dunn 功能描述:MERCURY DISP RELAY SPDT 24VDC 1A 制造商:Struthers-Dunn 功能描述:MERCURY DISP RELAY, SPDT, 24VDC, 1A; Coil Voltage VDC Nom:24V; Contact Current Max:1A; Contact Voltage DC Max:5kV; Coil Resistance:120ohm; Contact Configuration:SPDT; Breakover Voltage Min:7.5kV; Relay Mounting:Bracket; Depth:57.9mm ;RoHS Compliant: No 制造商:Magnecraft 功能描述:Electromechanical Relay SPST-NO-DM/SPST-NC-DB 1A 24VDC 120Ohm Bracket Mount
W159 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:Spread Spectrum System FTG for SMP Systems
W159B 制造商:SPECTRALINEAR 制造商全称:SPECTRALINEAR 功能描述:Spread Spectrum System FTG for SMP Systems