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參數(shù)資料
| 型號(hào)： | MPC9992ACR2 |
| 廠商： | FREESCALE SEMICONDUCTOR INC |
| 元件分類： | 時(shí)鐘產(chǎn)生/分配 |
| 英文描述： | 400 MHz, OTHER CLOCK GENERATOR, PQFP32 |
| 封裝： | 7 X 7 MM, 1.40 MM HEIGHT, LEAD FREE, MS-026BBA, LQFP-32 |
| 文件頁數(shù)： | 11/12頁 |
| 文件大?。?/td> | 313K |
| 代理商： | MPC9992ACR2 |
Advanced Clock Drivers Device Data
8
Freescale Semiconductor
MPC9992
Power Supply Filtering
The MPC9992 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 MPC9992 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
power supply filter scheme. The MPC9992 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 9 mA (12 mA maximum), assuming that a
minimum of 2.955 V must be maintained on the VCC_PLL pin.
10-15
to meet the voltage drop criteria.
Figure 4. VCC_PLL Power Supply Filter
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 Figure 4, the filter cut-off frequency is around
3-5 kHz and the noise attenuation at 100 kHz is better than
42 dB.
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 MPC9992 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.
Figure 5. MPC9992 AC Test Reference
VCC_PLL
VCC
MPC9992
10 nF
RF = 10 – 15
CF
33...100 nF
RF
VCC
CF = 22 F
Differential Pulse
Generator
Z = 50
RT = 50
Z = 50
RT = 50
MPC9992 DUT
VTT
Z = 50
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參數(shù)描述 |
|---|---|
| MPC9992FA | 功能描述:鎖相環(huán) - PLL 2.5 3.3V 400MHz 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 |
| MPC9992FAR2 | 制造商:Integrated Device Technology Inc 功能描述:PLL Clock Driver Single 32-Pin LQFP T/R |
| MPC9993 | 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:INTELLIGENT DYNAMIC CLOCK SWITCH (IDCS)PLL CLOCK DRIVER |
| MPC9993AC | 功能描述:時(shí)鐘驅(qū)動(dòng)器及分配 RoHS:否 制造商:Micrel 乘法/除法因子:1:4 輸出類型:Differential 最大輸出頻率:4.2 GHz 電源電壓-最大: 電源電壓-最小:5 V 最大工作溫度:+ 85 C 封裝 / 箱體:SOIC-8 封裝:Reel |
| MPC9993ACR2 | 功能描述:時(shí)鐘驅(qū)動(dòng)器及分配 RoHS:否 制造商:Micrel 乘法/除法因子:1:4 輸出類型:Differential 最大輸出頻率:4.2 GHz 電源電壓-最大: 電源電壓-最小:5 V 最大工作溫度:+ 85 C 封裝 / 箱體:SOIC-8 封裝:Reel |
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