參數(shù)資料
型號(hào): MPC9774
廠商: Motorola, Inc.
英文描述: 3.3V / 2,5V 1:14 LVCMOS PLL CLOCK GENERATOR
中文描述: 3.3 / 2,5 V 13:14:00的LVCMOS PLL時(shí)鐘發(fā)生器
文件頁(yè)數(shù): 11/16頁(yè)
文件大?。?/td> 217K
代理商: MPC9774
MPC9774
TIMING SOLUTIONS
11
MOTOROLA
Power Supply Filtering
The MPC9774 is a mixed analog/digital product. Its analog
circuitry is naturally susceptible to random noise, especially if
this noise is seen on the power supply pins. Random noise
on the VCC_PLL power supply impacts the device
characteristics, for instance I/O jitter. The MPC9774 provides
separate power supplies for the output buffers (VCC) and the
phase-locked loop (VCC_PLL) of the device.The purpose of
this design technique is to isolate the high switching noise
digital outputs from the relatively sensitive internal analog
phase-locked loop. In a digital system environment where it
is more difficult to minimize noise on the power supplies a
second level of isolation may be required. The simple but
effective form of isolation is a power supply filter on the
VCC_PLL pin for the MPC9774.
Figure 10 illustrates a typical
power supply filter scheme. The MPC9774 frequency and
phase stability is most susceptible to noise with spectral
content in the 100 kHz to 20 MHz range. Therefore the filter
should be designed to target this range. The key parameter
that needs to be met in the final filter design is the DC voltage
drop across the series filter resistor RF. From the data sheet
the ICC_PLL current (the current sourced through the
VCC_PLL pin) is typically 3 mA (5 mA maximum), assuming
that a minimum of 2.325V (VCC = 3.3V or VCC = 2.5V) must
be maintained on the VCC_PLL pin. The resistor RF shown in
MPC9774 must have a resistance of 9-10
(VCC = 2.5V) to
meet the voltage drop criteria.
The minimum values for RF and the filter capacitor CF are
defined by the required filter characteristics: the RC filter
should provide an attenuation greater than 40 dB for noise
whose spectral content is above 100 kHz. In the example RC
filter shown in MPC9774, the filter cut-off frequency is around
3-5 kHz and the noise attenuation at 100 kHz is better than
42 dB.
RF = 9–10
Figure 10. VCC Power Supply Filter
As the noise frequency crosses the series resonant point
of an individual capacitor its overall impedance begins to look
inductive and thus increases with increasing frequency. The
parallel capacitor combination shown ensures that a low
impedance path to ground exists for frequencies well above
the bandwidth of the PLL. Although the MPC9774 has
several design features to minimize the susceptibility to
power supply noise (isolated power and grounds and fully
differential PLL) there still may be applications in which
overall performance is being degraded due to system power
supply noise. The power supply filter schemes discussed in
this section should be adequate to eliminate power supply
noise related problems in most designs.
VCC_PLL
VCC
MPC9774
10 nF
CF
33...100 nF
RF
VCC
CF = 22
μ
F
Figure 11. CCLK MPC9774 AC test reference for Vcc = 3.3V and Vcc = 2.5V
Pulse
Generator
Z = 50
RT = 50
Z = 50
RT = 50
Z = 50
MPC9774 DUT
VTT
VTT
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MPC9774AE 功能描述:時(shí)鐘發(fā)生器及支持產(chǎn)品 3.3V 125MHz Clock Generator RoHS:否 制造商:Silicon Labs 類型:Clock Generators 最大輸入頻率:14.318 MHz 最大輸出頻率:166 MHz 輸出端數(shù)量:16 占空比 - 最大:55 % 工作電源電壓:3.3 V 工作電源電流:1 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-56
MPC9774AER2 功能描述:IC PLL CLK GEN 1:14 3.3V 52-LQFP RoHS:是 類別:集成電路 (IC) >> 時(shí)鐘/計(jì)時(shí) - 時(shí)鐘發(fā)生器,PLL,頻率合成器 系列:- 標(biāo)準(zhǔn)包裝:1,000 系列:- 類型:時(shí)鐘/頻率合成器,扇出分配 PLL:- 輸入:- 輸出:- 電路數(shù):- 比率 - 輸入:輸出:- 差分 - 輸入:輸出:- 頻率 - 最大:- 除法器/乘法器:- 電源電壓:- 工作溫度:- 安裝類型:表面貼裝 封裝/外殼:56-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:56-VFQFP-EP(8x8) 包裝:帶卷 (TR) 其它名稱:844S012AKI-01LFT
MPC9774FA 功能描述:鎖相環(huán) - PLL 3.3V 125MHz Clock Generator RoHS:否 制造商:Silicon Labs 類型:PLL Clock Multiplier 電路數(shù)量:1 最大輸入頻率:710 MHz 最小輸入頻率:0.002 MHz 輸出頻率范圍:0.002 MHz to 808 MHz 電源電壓-最大:3.63 V 電源電壓-最小:1.71 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:QFN-36 封裝:Tray
MPC9774FAR2 功能描述:時(shí)鐘發(fā)生器及支持產(chǎn)品 FSL 1-14 LVCMOS PLL Clock Generator RoHS:否 制造商:Silicon Labs 類型:Clock Generators 最大輸入頻率:14.318 MHz 最大輸出頻率:166 MHz 輸出端數(shù)量:16 占空比 - 最大:55 % 工作電源電壓:3.3 V 工作電源電流:1 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-56
MPC97H73AE 功能描述:IC PLL CLK GEN 1:12 3.3V 52-LQFP RoHS:是 類別:集成電路 (IC) >> 時(shí)鐘/計(jì)時(shí) - 時(shí)鐘發(fā)生器,PLL,頻率合成器 系列:- 標(biāo)準(zhǔn)包裝:1,000 系列:- 類型:時(shí)鐘/頻率合成器,扇出分配 PLL:- 輸入:- 輸出:- 電路數(shù):- 比率 - 輸入:輸出:- 差分 - 輸入:輸出:- 頻率 - 最大:- 除法器/乘法器:- 電源電壓:- 工作溫度:- 安裝類型:表面貼裝 封裝/外殼:56-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:56-VFQFP-EP(8x8) 包裝:帶卷 (TR) 其它名稱:844S012AKI-01LFT