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| 型号： | MPC92429EI |
| 厂商： | IDT, Integrated Device Technology Inc |
| 文件页数： | 12/13页 |
| 文件大小： | 0K |
| 描述： | IC SYNTHESIZER LVPECL 28-PLCC |
| 标准包装： | 37 |
| 类型： | 时钟/频率合成器 |
| PLL： | 是 |
| 输入： | 晶体 |
| 输出： | LVPECL |
| 电路数： | 1 |
| 比率 - 输入:输出： | 1:1 |
| 差分 - 输入:输出： | 无/是 |
| 频率 - 最大： | 400MHz |
| 除法器/乘法器： | 是/无 |
| 电源电压： | 3.135 V ~ 3.465 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-LCC（J 形引线） |
| 供应商设备封装： | 28-PLCC（11.5x11.5） |
| 包装： | 管件 |
MPC92429 REVISION 3 DECEMBER 14, 2012
8
2012 Integrated Device Technology, Inc.
MPC92429 Data Sheet
400 MHz Low Voltage PECL Clock Synthesizer
Figure 4. Serial Interface Timing Diagram
Power Supply Filtering
The MPC92429 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 pin impacts the device
characteristics. The MPC92429 provides separate power
supplies for the digital circuitry (VCC) and the internal PLL
(VCC_PLL) of the device. The purpose of this design technique
is to try and isolate the high switching noise digital outputs
from the relatively sensitive internal analog phase-locked
loop. In a controlled environment such as an evaluation
board, this level of isolation is sufficient. However, 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 simplest form of isolation is a power supply
illustrates a typical power supply filter scheme. The
MPC92429 is most susceptible to noise with spectral content
in the 1 kHz to 1 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 that
will be seen between the VCC supply and the MPC92429 pin
of the MPC92429. From the data sheet, the VCC_PLL current
(the current sourced through the VCC_PLL pin) is maximum
20 mA, assuming that a minimum of 2.835 V must be
maintained on the VCC_PLL pin. The resistor shown in
Figure 5 must have a resistance of 10-15
to meet the
voltage drop criteria. The RC filter pictured will provide a
broadband filter with approximately 100:1 attenuation for
noise whose spectral content is above 20 kHz. 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. Generally, the resistor/capacitor filter
will be cheaper, easier to implement and provide an adequate
level of supply filtering. A higher level of attenuation can be
achieved by replacing the resistor with an appropriate valued
inductor. A 1000
H choke will show a significant impedance
at 10 kHz frequencies and above. Because of the current
draw and the voltage that must be maintained on the VCC_PLL
pin, a low DC resistance inductor is required (less than 15
).
Figure 5. VCC_PLL Power Supply Filter
Layout Recommendations
The MPC92429 provides sub-nanosecond output edge
rates and thus a good power supply bypassing scheme is a
must. Figure 6 shows a representative board layout for the
MPC92429. There exists many different potential board
layouts and the one pictured is but one. The important aspect
of the layout in Figure 6 is the low impedance connections
between VCC and GND for the bypass capacitors. Combining
good quality general purpose chip capacitors with good PCB
layout techniques will produce effective capacitor resonances
at frequencies adequate to supply the instantaneous
switching current for the MPC92429 outputs. It is imperative
that low inductance chip capacitors are used; it is equally
important that the board layout does not introduce back all of
the inductance saved by using the leadless capacitors. Thin
interconnect traces between the capacitor and the power
plane should be avoided and multiple large vias should be
used to tie the capacitors to the buried power planes. Fat
interconnect and large vias will help to minimize layout
induced inductance and thus maximize the series resonant
point of the bypass capacitors. Note the dotted lines circling
the crystal oscillator connection to the device. The oscillator
is a series resonant circuit and the voltage amplitude across
the crystal is relatively small. It is imperative that no actively
switching signals cross under the crystal as crosstalk energy
coupled to these lines could significantly impact the jitter of
the device. Special attention should be paid to the layout of
2. Clocked out at the rate of S_CLOCK
(4N)
S_CLOCK
S_DATA
S_LOAD
M[8:0]
N[1:0]
P_LOAD
T2 T1
T0
N1
N0
M8
M7
M6
M5
M4
M3
M2
M1
M0
M, N
First
Bit
Last
Bit
VCC_PLL
VCC
MPC92429
C1, C2 = 0.01...0.1 F
VCC
CF = 22 F
RF = 10-15
C2
C1
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| MPC92429EIR2 | 功能描述:时钟合成器/抖动清除器 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 |
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| MPC92429FN | 制造商:MOTOROLA 制造商全称:Motorola, Inc 功能描述:400 MHz Low Voltage PECL Clock Synthesizer |
| MPC92432 | 制造商:MOTOROLA 制造商全称:Motorola, Inc 功能描述:1360 MHz Dual Output LVPECL Clock Synthesizer |
| MPC92432AE | 功能描述:时钟合成器/抖动清除器 FSL 1360MHz Dual Out put LVPECL Clock Syn 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 |
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