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参数资料
| 型号： | CY284108ZXC |
| 厂商： | Silicon Laboratories Inc |
| 文件页数： | 15/16页 |
| 文件大小： | 0K |
| 描述： | IC CLOCK SERV CK410B 56TSSOP |
| 标准包装： | 35 |
| 类型： | 时钟/频率发生器 |
| PLL： | 是 |
| 主要目的： | Intel CPU 服务器 |
| 输入： | 晶体 |
| 输出： | HCSL，LVCMOS |
| 电路数： | 1 |
| 比率 - 输入:输出： | 1:19 |
| 差分 - 输入:输出： | 无/是 |
| 频率 - 最大： | 400MHz |
| 电源电压： | 3.135 V ~ 3.465 V |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 56-TFSOP（0.240"，6.10mm 宽） |
| 供应商设备封装： | 56-TSSOP |
| 包装： | 管件 |
CY284108
........................ Document #: 38-07713 Rev. *B Page 8 of 16
The CY284108 requires a parallel resonance crystal. Substi-
tuting a series resonance crystal will cause the CY284108 to
operate at the wrong frequency and violate the ppm specifi-
cation. For most applications there is a 300-ppm frequency
shift between series and parallel crystals due to incorrect
loading.
Crystal Loading
Crystal loading plays a critical role in achieving low ppm perfor-
mance. To realize low ppm performance, the total capacitance
the crystal will see must be considered to calculate the appro-
priate capacitive loading (CL).
Figure shows a typical crystal configuration using the two trim
capacitors. An important clarification for the following
discussion is that the trim capacitors are in series with the
crystal not parallel. It is a common misconception that load
capacitors are in parallel with the crystal and should be
approximately equal to the load capacitance of the crystal.
This is not true.
Calculating Load Capacitors
In addition to the standard external trim capacitors, trace
capacitance and pin capacitance must also be considered to
correctly calculate crystal loading. As mentioned previously,
the capacitance on each side of the crystal is in series with the
crystal. This means the total capacitance on each side of the
crystal must be twice the specified crystal load capacitance
(CL). While the capacitance on each side of the crystal is in
series with the crystal, trim capacitors (Ce1,Ce2) should be
calculated to provide equal capacitive loading on both sides.
Figure 2.
Use the following formulas to calculate the trim capacitor
values for Ce1 and Ce2.
CL....................................................Crystal load capacitance
CLe......................................... Actual loading seen by crystal
using standard value trim capacitors
Ce..................................................... External trim capacitors
Cs .............................................. Stray capacitance (terraced)
Ci ...........................................................Internal capacitance
(lead frame, bond wires etc.)
PD (Power-down) Clarification
The VTT_PWRGD# /PD pin is a dual-function pin. During
initial power up, the pin functions as VTT_PWRGD#. Once
VTT_PWRGD# has been sampled low by the clock chip, the
pin assumes PD functionality. The PD pin is an asynchronous
active HIGH input used to shut off all clocks cleanly prior to
shutting off power to the device. This signal is synchronized
internal to the device prior to powering down the clock synthe-
sizer. PD is also an asynchronous input for powering up the
system. When PD is asserted high, drive all clocks to a low
value and hold prior to turning off the VCOs and the crystal
oscillator.
Table 5. Crystal Recommendations
Frequency
(Fund)
Cut
Loading
Load Cap
Drive
(max.)
Shunt Cap
(max.)
Motional
(max.)
Tolerance
(max.)
Stability
(max.)
Aging
(max.)
14.31818 MHz
AT
Parallel
20 pF
0.1 mW
5 pF
0.016 pF
35 ppm
30 ppm
5 ppm
Figure 1. Crystal Capacitive Clarification
XTAL
Ce2
Ce1
Cs1
Cs2
X1
X2
Ci1
Ci2
Clock Chip
Trace
2.8 pF
Trim
33 pF
Pin
3 to 6p
Figure 3. Crystal Loading Example
Load Capacitance (each side)
Total Capacitance (as seen by the crystal)
Ce = 2 * CL – (Cs + Ci)
Ce1 + Cs1 + Ci1
1
+
Ce2 + Cs2 + Ci2
1
()
1
=
CLe
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相关代理商/技术参数 |
参数描述 |
|---|---|
| CY284108ZXCT | 功能描述:时钟发生器及支持产品 Server, CK410B RoHS:否 制造商:Silicon Labs 类型:Clock Generators 最大输入频率:14.318 MHz 最大输出频率:166 MHz 输出端数量:16 占空比 - 最大:55 % 工作电源电压:3.3 V 工作电源电流:1 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-56 |
| CY28410OC | 制造商:SPECTRALINEAR 制造商全称:SPECTRALINEAR 功能描述:Clock Generator for Intel Grantsdale Chipset |
| CY28410OCT | 制造商:SPECTRALINEAR 制造商全称:SPECTRALINEAR 功能描述:Clock Generator for Intel Grantsdale Chipset |
| CY28410OXC | 功能描述:时钟发生器及支持产品 SysClk Intel Lakeprt & Grantsdale Chipset RoHS:否 制造商:Silicon Labs 类型:Clock Generators 最大输入频率:14.318 MHz 最大输出频率:166 MHz 输出端数量:16 占空比 - 最大:55 % 工作电源电压:3.3 V 工作电源电流:1 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-56 |
| CY28410OXC-2 | 功能描述:时钟发生器及支持产品 SysClk Intel Lakeprt & Grantsdale Chipset RoHS:否 制造商:Silicon Labs 类型:Clock Generators 最大输入频率:14.318 MHz 最大输出频率:166 MHz 输出端数量:16 占空比 - 最大:55 % 工作电源电压:3.3 V 工作电源电流:1 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-56 |
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