參數(shù)資料
型號： LTC4266CUHF#PBF
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)： 9/30頁
文件大小： 414K
代理商： LTC4266CUHF#PBF
LTC4266
4266fa
ApplicAtions inForMAtion
OperatingModes
TheLTC4266includesfourindependentports,eachof
whichcanoperateinoneoffourmodes:Manual,Semi-
auto,Auto,orShutdown.
Inmanualmode,theportwaitsforinstructionsfromthe
hostsystembeforetakinganyaction.Itrunsasingle
detectionorclassificationcyclewhencommandedto
bythehost,andreportstheresultinitsPortStatus
register.Thehostsystemcancommandtheportto
turnonoroffthepoweratanytime.
In semi-auto mode, the port repeatedly attempts to
detectandclassifyanyPDattachedtoit.Itreportsthe
statusoftheseattemptsbacktothehost,andwaitsfor
acommandfromthehostbeforeturningonpowerto
theport.Thehostmustenabledetection(andoptionally
classification)fortheportbeforedetectionwillstart.
AutomodeoperatesthesameasSemi-automodeexcept
thatitwillautomaticallyturnonthepowertotheport
ifdetectionissuccessful.
Inshutdownmode,theportisdisabledandwillnot
detectorpoweraPD.
Regardlessofwhichmodeitisin,theLTC4266willremove
powerautomaticallyfromanyportthatgeneratesacurrent
limitfault.Itwillalsoautomaticallyremovepowerfrom
anyportthatgeneratesadisconnecteventifdisconnect
detectionisenabled.Thehostcontrollermayalsocom-
mandtheporttoremovepoweratanytime.
Power-OnResetandtheAUTO/MIDpins
TheinitialLTC4266configurationdependsonthestate
oftheAUTOandMIDpinsduringreset.Resetoccursat
power-up,orwhenevertheRESETpinispulledloworthe
globalResetAllbitisset.NotethattheAUTOpinisonly
sampledwhenaresetoccurs.ChangingthestateofAUTO
orMIDafterpower-upwillnotchangetheportbehavior
oftheLTC4266untilaresetoccurs.
Althoughtypicallyusedwithahostcontroller,theLTC4266
canalsobeusedinastandalonemodewithnoconnection
totheserialinterface.Ifthereisnohostpresent,theAUTO
pinshouldbetiedhighsothat,atreset,allportswillbe
configuredtooperateautomatically.Eachportwilldetect
andclassifyrepeatedlyuntilaPDisdiscovered,setICUT
andILIMaccordingtotheclassificationresults,applypower
aftersuccessfuldetection,andremovepowerwhenaPD
isdisconnected.Similarly,ifthestandaloneapplication
isamidspan,theMIDpinshouldbetiedhightoenable
correctmidspandetectiontiming.
Table 1 shows the ICUT and ILIM values that will be
automaticallysetinstandalonemode,basedonthedis-
coveredclass.
Table1.ICUTandILIMValuesinStandaloneMode
CLASS
ICUT
ILIM
Class1
112mA
425mA
Class2
206mA
425mA
Class3orClass0
375mA
425mA
Class4
638mA
850mA
TheautomaticsettingoftheICUTandILIMvaluesonlyoc-
cursiftheLTC4266isresetwiththeAUTOpinhigh.
DETECTION
DetectionOverview
Toavoiddamagingnetworkdevicesthatwerenotdesigned
totolerateDCvoltage,aPSEmustdeterminewhetherthe
connecteddeviceisarealPDbeforeapplyingpower.The
IEEEspecificationrequiresthatavalidPDhaveacommon-
moderesistanceof25k±5%atanyportvoltagebelow
10V.ThePSEmustacceptresistancesthatfallbetween
19kand26.5k,anditmustrejectresistancesabove
33korbelow15k(shadedregionsinFigure11).The
PSEmaychoosetoacceptorrejectresistancesinthe
undefinedareasbetweenthemust-acceptandmust-reject
ranges.Inparticular,thePSEmustrejectstandardcomputer
networkports,manyofwhichhave150Ωcommon-mode
terminationresistorsthatwillbedamagedifpowerisap-
pliedtothem(theblackregionattheleftofFigure11).
RESISTANCE
PD
PSE
0
10k
15k
4266 F11
19k
26.5k
26.25k
23.75k
150 (NIC)
20k
30k
33k
Figure11.IEEE802.3afSignatureResistanceRanges
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC4266IGW#PBF 功能描述:IC CTRLR IEEE 802.3AT 36-SSOP 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
LTC4266IGW#TRPBF 制造商:Linear Technology 功能描述:Power Over Ethernet Controller 36-Pin SSOP W T/R 制造商:Linear Technology 功能描述:MS-Hot Swap/POE, PoE+ 25.5W Quad PSE Controller
LTC4266IUHF#PBF 制造商:Linear Technology 功能描述:POE Controller 25.5W 38-Pin QFN EP 制造商:Linear Technology 功能描述:IC POE 802.3AT QUAD PSE 38-QFN 制造商:Linear Technology 功能描述:POE CNTRL QUAD 25.5W 1MHZ 制造商:Linear Technology 功能描述:IC, POE CONTROLLER, 3.3V, QFN-38; Input Voltage:3.3V; Supply Current:-2.4mA; UVLO:25V; Digital IC Case Style:QFN; No. of Pins:38; Frequency:1MHz; Operating Temperature Min:-40C; Operating Temperature Max:85C; MSL:MSL 1 - Unlimited ;RoHS Compliant: Yes
LTC4266IUHF#TRPBF 制造商:Linear Technology 功能描述:POE Controller 25.5W 38-Pin QFN EP
LTC4267 制造商:LINER 制造商全稱:Linear Technology 功能描述:Quad IEEE 802.3at Power over Ethernet Controller
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