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| 型号： | ICS8431AM-21LF |
| 厂商： | INTEGRATED DEVICE TECHNOLOGY INC |
| 元件分类： | 时钟产生/分配 |
| 英文描述： | 350 MHz, OTHER CLOCK GENERATOR, PDSO28 |
| 封装： | 7.50 X 18.05 MM, 2.25 MM HEIGHT, ROHS COMPLIANT, MS-013, MO-119, SOIC-28 |
| 文件页数： | 18/19页 |
| 文件大小： | 342K |
| 代理商： | ICS8431AM-21LF |
IDT / ICS 3.3V LVPECL FREQUENCY SYNTHESIZER
8
ICS8431AM-21 REV. A MAY 30, 2007
ICS8431-21
350MHZ, LOW JITTER, CRYSTAL OSCILLATOR-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
As in any high speed analog circuitry, the power supply pins
are vulnerable to random noise. The ICS8431-21 provides sepa-
rate power supplies to isolate any high switching noise from
the outputs to the internal PLL. V
CC, VCCA, and VCCO should be
individually connected to the power supply plane through vias,
and bypass capacitors should be used for each pin. To achieve
optimum jitter performance, better power supply isolation is
required. Figure 1 illustrates how a 10
Ω along with a 10μF and
a .01
μF bypass capacitor should be connected to each V
CCA
pin.
FIGURE 1. POWER SUPPLY FILTERING
10
Ω
V
CCA
10
μF
.01
μF
3.3V
.01
μF
V
CC
POWER SUPPLY FILTERING TECHNIQUES
APPLICATION INFORMATION
SPREAD SPECTRUM
Spread-spectrum clocking is a frequency modulation technique
for EMI reduction. When spread-spectrum is enabled, a 30kHz
triangle waveform is used with 0.5% down-spread (+0.0% / -
0.5%) from the nominal 200MHz clock frequency. An example
of a triangle frequency modulation profile is shown in Figure
2A below. The ramp profile can be expressed as:
Fnom = Nominal Clock Frequency in Spread OFF mode
(200MHz with 16MHz IN)
Fm = Nominal Modulation Frequency (30kHz)
δ = Modulation Factor (0.5% down spread)
The ICS8431-21 triangle modulation frequency deviation will
not exceed 0.6% down-spread from the nominal clock frequency
(+0.0% / -0.5%). An example of the amount of down spread
relative to the nominal clock frequency can be seen in the fre-
quency domain, as shown in Figure 2B. The ratio of this width
to the fundamental frequency is typically 0.4%, and will not
exceed 0.6%. The resulting spectral reduction will be greater
than 7dB, as shown in Figure 2B. It is important to note the
ICS8431-21 7dB minimum spectral reduction is the component-
specific EMI reduction, and will not necessarily be the same as
the system EMI reduction.
FIGURE 2B. 200MHZ CLOCK OUTPUT IN FREQUENCY DOMAIN
(A) SPREAD-SPECTRUM OFF (B) SPREAD-SPECTRUM ON
FIGURE 2A. TRIANGLE FREQUENCY MODULATION
(1 -
δ) fnom + 2 fm x δ x fnom x t when 0 < t <
,
(1 -
δ) fnom - 2 fm x δ x fnom x t when
< t <
1
2fm
1
2fm
1
fm
Δ 10 dBm
δ = .4%
B
A
Fnom
(1 -
δ) Fnom
0.5/fm
1/fm
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ICS8431AM-21LFT | 功能描述:IC SYNTHESIZER 350MHZ 28-SOIC RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 时钟发生器，PLL，频率合成器 系列:HiPerClockS™ 标准包装:1,000 系列:- 类型:时钟/频率合成器，扇出分配 PLL:- 输入:- 输出:- 电路数:- 比率 - 输入:输出:- 差分 - 输入:输出:- 频率 - 最大:- 除法器/乘法器:- 电源电压:- 工作温度:- 安装类型:表面贴装 封装/外壳:56-VFQFN 裸露焊盘 供应商设备封装:56-VFQFP-EP（8x8） 包装:带卷 (TR) 其它名称:844S012AKI-01LFT |
| ICS8431AM-21T | 制造商:ICS 制造商全称:ICS 功能描述:350MHZ, LOW JITTER, CRYSTAL OSCILLATOR-TO-3.3V LVPECL FREQUENCY SYNTHESIZER |
| ICS8431AMI-21 | 制造商:ICS 制造商全称:ICS 功能描述:350MHZ, LOW JITTER, CRYSTAL OSCILLATOR-TO-3.3V LVPECL FREQUENCY SYNTHESIZER |
| ICS8431AMI-21LF | 功能描述:IC SYNTHESIZER 350MHZ 28-SOIC RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 时钟发生器，PLL，频率合成器 系列:HiPerClockS™ 标准包装:27 系列:Precision Edge® 类型:频率合成器 PLL:是 输入:PECL，晶体 输出:PECL 电路数:1 比率 - 输入:输出:1:1 差分 - 输入:输出:无/是 频率 - 最大:800MHz 除法器/乘法器:是/无 电源电压:3.135 V ~ 5.25 V 工作温度:0°C ~ 85°C 安装类型:表面贴装 封装/外壳:28-SOIC（0.295"，7.50mm 宽） 供应商设备封装:28-SOIC 包装:管件 |
| ICS8431AMI-21LFT | 功能描述:IC SYNTHESIZER 350MHZ 28-SOIC RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 时钟发生器，PLL，频率合成器 系列:HiPerClockS™ 标准包装:1,000 系列:- 类型:时钟/频率合成器，扇出分配 PLL:- 输入:- 输出:- 电路数:- 比率 - 输入:输出:- 差分 - 输入:输出:- 频率 - 最大:- 除法器/乘法器:- 电源电压:- 工作温度:- 安装类型:表面贴装 封装/外壳:56-VFQFN 裸露焊盘 供应商设备封装:56-VFQFP-EP（8x8） 包装:带卷 (TR) 其它名称:844S012AKI-01LFT |
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