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参数资料
| 型号： | CY28548ZXCT |
| 厂商： | Silicon Laboratories Inc |
| 文件页数： | 8/30页 |
| 文件大小： | 0K |
| 描述： | IC CLK CK505 960M/965M 64TSSOP |
| 标准包装： | 2,000 |
| 类型： | 时钟/频率发生器 |
| PLL： | 是 |
| 主要目的： | Intel CPU 服务器 |
| 输入： | 时钟 |
| 输出： | LVCMOS |
| 电路数： | 1 |
| 比率 - 输入:输出： | 3:22 |
| 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 ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 64-TFSOP （0.240"，6.10mm 宽） |
| 供应商设备封装： | 64-TSSOP |
| 包装： | 带卷 (TR) |
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CY28548
......................Document #: 001-08400 Rev ** Page 16 of 30
The CY28548 requires a Parallel Resonance Crystal. Substi-
tuting a series resonance crystal causes the CY28548 to
operate at the wrong frequency and violates 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, use the total capac-
itance the crystal sees to calculate the appropriate capacitive
loading (CL).
Figure 1 shows a typical crystal configuration using the two
trim capacitors. It is important that the trim capacitors are in
series with the crystal. It is not true that load capacitors are in
parallel with the crystal and are approximately equal to the
load capacitance of the crystal.
Calculating Load Capacitors
In addition to the standard external trim capacitors, consider
the trace capacitance and pin capacitance to calculate the
crystal loading correctly. Again, the capacitance on each side
is in series with the crystal. The total capacitance on both side
is twice the specified crystal load capacitance (CL). Trim
capacitors are calculated to provide equal capacitive loading
on both sides.
,
Use the following formulas to calculate the trim capacitor
values for Ce1 and Ce2.
7
0
SMSW_EN
Enable Smooth Switching
0 = Disabled, 1= Enabled
6
0
SMSW_SEL
Smooth switch select
0 = CPU_PLL, 1 = SRC_PLL
5
0
SE1/SE2 drive strength
2 of 2
SE1 and SE2 drive strength Setting 2 of 2
4
0
Prog_PCI-E_EN
Programmable PCI-E frequency enable
0 = Disabled, 1= Enabled
3
0
Prog_CPU_EN
Programmable CPU frequency enable
0 = Disabled, 1= Enabled
2
0
REF drive strength
2 of 2
REFdrive strength strength Setting 2 of 2
1
0
USB drive strength
2 of 2
USB drive strength strength Setting 2 of 2
0
PCI/ PCIF drive strength
2of 2
PCI drive strength strength Setting 2 of 2
Byte 17: Control Register 17 (continued)
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
Ce 2
Ce 1
Cs 1
Cs 2
X1
X2
Ci1
Ci2
Clo c k Ch ip
Tr a c e
2. 8pF
Tr im
33pF
Pin
3 t o 6p
Figure 2. 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 |
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| CY28551 | 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:Universal Clock Generator for Intel, VIA, and SIS㈢ |
| CY28551-3 | 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:Universal Clock Generator for Intel, VIA and SIS㈢ |
| CY28551LFXC | 功能描述:时钟发生器及支持产品 Universal System Clk Intel AMD SiS Via 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 |
| CY28551LFXC-3 | 功能描述:时钟发生器及支持产品 Universal System Clk Intel AMD SiS Via 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 |
| CY28551LFXC-3T | 功能描述:时钟发生器及支持产品 Universal System Clk Intel AMD SiS Via 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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