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參數(shù)資料
| 型號(hào)： | MPC9330 |
| 廠(chǎng)商： | Motorola, Inc. |
| 英文描述： | 3.3V / 2.5V 1:6 LVCMOS PLL CLOCK GENERATOR |
| 中文描述： | 3.3 / 2.5V的1:6的LVCMOS PLL時(shí)鐘發(fā)生器 |
| 文件頁(yè)數(shù)： | 9/16頁(yè) |
| 文件大?。?/td> | 225K |
| 代理商： | MPC9330 |
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MPC9330
TIMING SOLUTIONS
9
MOTOROLA
APPLICATIONS INFORMATION
Power Supply Filtering
The MPC9330 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 VCCA_PLL power supply impacts the device
characteristics, for instance I/O jitter. The MPC9330 provides
separate power supplies for the output buffers (VCC) and the
phase-locked loop (VCCA) 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 MPC9330. Figure 3. illustrates a typical
power supply filter scheme. The MPC9330 frequency and
phase stability is most susceptible to noise with spectral
content in the 100kHz to 20MHz 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 ICCA 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
Figure 3. “VCC_PLL Power Supply Filter” must have a
resistance of 270 (VCC=3.3V) or 9-10 (VCC=2.5V) to meet
the voltage drop criteria.
Figure 3. VCC_PLL Power Supply Filter
VCC_PLL
VCC
MPC9330
10 nF
RF = 270
for VCC = 3.3V
RF = 9–10
for VCC = 2.5V
CF
33...100 nF
RF
VCC
CF = 1
μ
F for VCC = 3.3V
CF = 22
μ
F for VCC = 2.5V
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 3. “VCC_PLL Power Supply Filter”, 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 MPC9330 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.
Driving Transmission Lines
The MPC9330 clock driver was designed to drive high
speed signals in a terminated transmission line environment.
To provide the optimum flexibility to the user the output
drivers were designed to exhibit the lowest impedance
possible. With an output impedance of less than 20
the
drivers can drive either parallel or series terminated
transmission lines. For more information on transmission
lines the reader is referred to Motorola application note
AN1091. In most high performance clock networks
point-to-point distribution of signals is the method of choice.
In a point-to-point scheme either series terminated or parallel
terminated transmission lines can be used. The parallel
technique terminates the signal at the end of the line with a
50
resistance to VCC
÷
2.
This technique draws a fairly high level of DC current and
thus only a single terminated line can be driven by each
output of the MPC9330 clock driver. For the series terminated
case however there is no DC current draw, thus the outputs
can drive multiple series terminated lines. Figure 4. “Single
versus Dual Transmission Lines” illustrates an output driving
a single series terminated line versus two series terminated
lines in parallel. When taken to its extreme the fanout of the
MPC9330 clock driver is effectively doubled due to its
capability to drive multiple lines.
Figure 4. Single versus Dual Transmission Lines
The waveform plots in Figure 5. “Single versus Dual Line
Termination Waveforms” show the simulation results of an
output driving a single line versus two lines. In both cases the
drive capability of the MPC9330 output buffer is more than
sufficient to drive 50
transmission lines on the incident
edge. Note from the delay measurements in the simulations a
delta of only 43ps exists between the two differently loaded
outputs. This suggests that the dual line driving need not be
used exclusively to maintain the tight output-to-output skew
of the MPC9330. The output waveform in Figure 5. “Single
14
IN
MPC9330
OUTPUT
BUFFER
RS = 36
ZO = 50
OutA
14
IN
MPC9330
OUTPUT
BUFFER
RS = 36
ZO = 50
OutB0
RS = 36
ZO = 50
OutB1
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MPC9330AC | 功能描述:時(shí)鐘發(fā)生器及支持產(chǎn)品 FSL 1-6 LVCMOS PLL Clock Generator RoHS:否 制造商:Silicon Labs 類(lèi)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 |
| MPC9330ACR2 | 功能描述:IC PLL CLOCK GENERATOR 32-LQFP RoHS:是 類(lèi)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(lèi)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(lèi)型:表面貼裝 封裝/外殼:56-VFQFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:56-VFQFP-EP（8x8） 包裝:帶卷 (TR) 其它名稱(chēng):844S012AKI-01LFT |
| MPC9330FA | 功能描述:時(shí)鐘發(fā)生器及支持產(chǎn)品 3.3V 200MHz Clock Generator RoHS:否 制造商:Silicon Labs 類(lèi)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 |
| MPC9330FAR2 | 制造商:Integrated Device Technology Inc 功能描述:MPC9330FAR2 - Tape and Reel |
| MPC9331 | 制造商:MOTOROLA 制造商全稱(chēng):Motorola, Inc 功能描述:3.3 V 1:6 LVCMOS PLL Clock Generator |
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