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參數(shù)資料
| 型號： | LTC4266IUHF#TRPBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 電源管理 |
| 英文描述： | POWER SUPPLY MANAGEMENT CKT, PQCC38 |
| 封裝： | 5 X 7 MM, LEAD FREE, PLASTIC, MO-220WHKD, QFN-38 |
| 文件頁數(shù)： | 7/30頁 |
| 文件大小： | 414K |
| 代理商： | LTC4266IUHF#TRPBF |
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LTC4266
4266fa
operAtion
Figure10.PowerOverEthernetSystemDiagram
4266 F10
S1B
SMAJ58A
0.22F
100V
X7R
1F
100V
X7R
Tx
Rx
Tx
SMAJ58A
58V
DATA PAIR
VEE SENSE GATE OUT
VDD
INT
SCL
SDAIN
SDAOUT
0.25
IRFM120A
SPARE PAIR
1/4
LTC4266
DGND
AGND
I2C
3.3V
INTERRUPT
–48V
CAT 5
20 MAX
ROUNDTRIP
0.05F MAX
RJ45
4
5
4
5
1
2
1
2
3
6
3
6
7
8
7
8
RJ45
1N4002
4
1N4002
4
PSE
PD
RCLASS
–48VIN
PWRGD
–48VOUT
LTC4265
GND
DC/DC
CONVERTER
5F ≤ CIN
≤ 300F
+
–
VOUT
GND
0.1F
Overview
PoweroverEthernet,orPoE,isastandardprotocolfor
sending DC power over copper Ethernet data wiring.
TheIEEEgroupthatadministersthe802.3Ethernetdata
standardsaddedPoEpoweringcapabilityin2003.This
originalPoEspec,knownas802.3af,allowedfor48VDC
poweratupto13W.Thisinitialspecwaswidelypopular,
but 13W was not adequate for some requirements. In
2009,theIEEEreleasedanewstandard,knownas802.3at
orPoE+,increasingthevoltageandcurrentrequirements
toprovide25Wofpower.
TheIEEEstandardalsodefinesPoEterminology.Adevice
thatprovidespowertothenetworkisknownasaPSE,or
powersourcingequipment,whileadevicethatdrawspower
fromthenetworkisknownasaPD,orpowereddevice.
PSEs come in two types: Endpoints (typically network
switchesorrouters),whichprovidedataandpower;and
Midspans,whichprovidepowerbutpassthroughdata.
MidspansaretypicallyusedtoaddPoEcapabilitytoexisting
non-PoEnetworks.PDsaretypicallyIPphones,wireless
accesspoints,securitycameras,andsimilardevices,but
couldbenearlyanythingthatrunsfrom25Worlessand
includesanRJ45-stylenetworkconnector.
TheLTC4266isathird-generationquadPSEcontroller
thatimplementsfourPSEportsineitheranendpointor
midspandesign.Virtuallyallnecessarycircuitryisincluded
toimplementaIEEE802.3atcompliantPSEdesign,requir-
ingonlyanexternalpowerMOSFETandsenseresistorper
channel;theseminimizepowerlosscomparedtoalterna-
tivedesignswithon-boardMOSFETsandincreasesystem
reliabilityintheeventasinglechannelisdamaged.
PoEBasics
CommonEthernetdataconnectionsconsistoftwoorfour
twistedpairsofcopperwire(commonlyknownasCAT-5
cable),transformer-coupledateachendtoavoidground
loops.PoEsystemstakeadvantageofthiscouplingar-
rangementbyapplyingvoltagebetweenthecenter-taps
ofthedatatransformerstotransmitpowerfromthePSE
tothePDwithoutaffectingdatatransmission.Figure10
showsahigh-levelPoEsystemschematic.
Toavoiddamaginglegacydataequipmentthatdoesnot
expecttoseeDCvoltage,thePoEspecdefinesaprotocol
that determines when the PSE may apply and remove
power.ValidPDsarerequiredtohaveaspecific25kΩ
common-moderesistanceattheirinput.WhensuchaPD
isconnectedtothecable,thePSEdetectsthissignature
resistanceandturnsonthepower.WhenthePDislater
disconnected,thePSEsensestheopencircuitandturns
poweroff.ThePSEalsoturnsoffpowerintheeventofa
currentfaultorshortcircuit.
WhenaPDisdetected,thePSEoptionallylooksfora
classificationsignaturethattellsthePSEthemaximum
powerthePDwilldraw.ThePSEcanusethisinformation
toallocatepoweramongseveralports,policethecurrent
consumptionofthePD,ortorejectaPDthatwilldraw
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| LTC6603CUF#TRPBF | LOW PASS FILTER |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC4267 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Quad IEEE 802.3at Power over Ethernet Controller |
| LTC4267-1 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Power over Ethernet IEEE 802.3af PD Interface with Integrated Switching Regulator |
| LTC4267-3 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Power over Ethernet IEEE 802.3af PD Interface with Integrated Switching Regulator |
| LTC4267CDHC | 制造商:Linear Technology 功能描述:Hot Swap Controller 1-CH -57V 16-Pin DFN EP |
| LTC4267CDHC#PBF | 功能描述:IC POE 802.3AF INTERFACE 16-DFN RoHS:是 類別:集成電路 (IC) >> 接口 - 控制器 系列:- 標(biāo)準(zhǔn)包裝:2,450 系列:- 控制器類型:SPI 總線至 I²C 總線橋接 接口:I²C，串行，SPI 電源電壓:2.4 V ~ 3.6 V 電流 - 電源:11mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:24-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:24-HVQFN（4x4） 包裝:托盤 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名稱:935286452157SC18IS600IBSSC18IS600IBS-ND |
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