- 您现在的位置：买卖IC网 > PDF目录380119 > CY2287 (Cypress Semiconductor Corp.) 100-MHz Spread Spectrum Clock Synthesizer/Driver with USB, Hublink, and SDRAM Support PDF资料下载
参数资料
| 型号： | CY2287 |
| 厂商： | Cypress Semiconductor Corp. |
| 英文描述： | 100-MHz Spread Spectrum Clock Synthesizer/Driver with USB, Hublink, and SDRAM Support |
| 中文描述： | 100 MHz的扩频时钟合成器/驱动器，带有USB接口，Hublink，和SDRAM支持 |
| 文件页数： | 12/13页 |
| 文件大小： | 148K |
| 代理商： | CY2287 |
CY2287
12
Application Information
Clock traces must be terminated with either series or parallel termination, as they are normally done.
Application Circuit
Summary
A parallel-resonant crystal should be used as the reference to the clock generator. The operating frequency and C
of
this crystal should be as specified in the data sheet. Optional trimming capacitors may be needed if a crystal with a different
C
LOAD
is used. Footprints must be laid out for flexibility.
Surface mount, low-ESR, ceramic capacitors should be used for filtering. Typically, these capacitors have a value of 2.2 nF.
In some cases, smaller value capacitors may be required.
The value of the series terminating resistor satisfies the following equation, where R
is the loaded characteristic impedance
of the trace, R
is the output impedance of the clock generator (CPU/APIC = 29 Ohm, USB/REF = 40 Ohm, SDRAM (3.3V)=
16 Ohm, PCI/3V66 = 30 Ohm - all nominal driver output impedances), and R
series
is the series terminating resistor.
R
series
> R
trace
–
R
out
Footprints must be laid out for optional EMI-reducing capacitors, which should be placed as close to the terminating resistor
as is physically possible. Typical values of these capacitors range from 4.7 pF to 22 pF.
A Ferrite Bead
may
be used to isolate the Board V
from the clock generator V
island. Ensure that the Ferrite Bead offers
greater than 50
impedance at the clock frequency, under loaded DC conditions. Please refer to the application note
“
Layout
and Termination Techniques for Cypress Clock Generators
”
for more details.
If a Ferrite Bead is used, a 10
μ
F
–
22
μ
F tantalum bypass capacitor should be placed close to the Ferrite Bead. This capacitor
prevents power supply droop during current surges.
XTALIN
XTALOUT
PWR_DWN
SEL0
SEL1
PWR_DWN
Rs
Ct
VDD3.3V
VDD2.5V
VSS
CPU
PCI
HUBLINK
APIC
SDRAM
REF
USB
CPU
SDRAM
PCI
3V66
APIC
REF
USB
Cx
Cd
Cd
CY2287-1 56 Pin SSOP
Cd = Decoupling Capacitors (
NOTE: May use 0.1
μ
F, but value will vary with frequency of operation and output current
)
Ct = Optional EMI-Reducing Capacitors
Cx = Optional Load Matching Capacitors
Rs = Termination Resistor
3.3V VDD
2.5V VDD
SEL0
SEL1
相关PDF资料 |
PDF描述 |
|---|---|
| CY2287-1 | 100-MHz Spread Spectrum Clock Synthesizer/Driver with USB, Hublink, and SDRAM Support |
| CY2287PVC-1 | 100-MHz Spread Spectrum Clock Synthesizer/Driver with USB, Hublink, and SDRAM Support |
| CY22K7 | 133-MHz Spread Spectrum Clock Generator For Use With the AMD-K7 Processor and AMD-750 Chipset |
| CY22K7PVC-1 | 133-MHz Spread Spectrum Clock Generator For Use With the AMD-K7 Processor and AMD-750 Chipset |
| CY23020LFI-3 | 10-output, 400-MHz LVPECL Zero Delay Buffer |
相关代理商/技术参数 |
参数描述 |
|---|---|
| CY2287-1 | 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:100-MHz Spread Spectrum Clock Synthesizer/Driver with USB, Hublink, and SDRAM Support |
| CY2287PVC-1 | 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:100-MHz Spread Spectrum Clock Synthesizer/Driver with USB, Hublink, and SDRAM Support |
| CY2291 | 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:Three-PLL General Purpose EPROM Programmable Clock Generator |
| CY2291_02 | 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:Three-PLL General Purpose EPROM Programmable Clock Generator |
| CY2291_08 | 制造商:CYPRESS 制造商全称:Cypress Semiconductor 功能描述:Three-PLL General Purpose EPROM Programmable Clock Generator |
发布紧急采购，3分钟左右您将得到回复。