參數資料
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： 11/30頁
文件大?。?/td> 414K
代理商： LTC4266CUHF#PBF
LTC4266
4266fa
ApplicAtions inForMAtion
capacitance(>10μF)asthedetectionsignature.Notethat
PDsinthisrangeofcapacitancearedefinedasinvalid,so
aPSEthatdetectslegacyPDsistechnicallynoncompliant
withtheIEEEspec.
TheLTC4266canbeconfiguredtodetectthistypeoflegacy
PD.Legacydetectionisdisabledbydefault,butcanbe
manuallyenabledonaper-portbasis.Whenenabled,the
portwillreportdetectgoodwhenitseeseitheravalidIEEE
PDorahigh-capacitancelegacyPD.Withlegacymode
disabled,onlyvalidIEEEPDswillberecognized.
CLASSIFICATION
802.3afClassification
APDcanoptionallypresentaclassificationsignatureto
thePSEtoindicatethemaximumpoweritwilldrawwhile
operating.TheIEEEspecificationdefinesthissignatureas
aconstantcurrentdrawwhenthePSEportvoltageisinthe
VCLASSrange(between15.5Vand20.5V),withthecurrent
levelindicatingoneof5possiblePDclasses.Figure14
showsatypicalPDloadline,startingwiththeslopeof
the25ksignatureresistorbelow10V,thentransitioning
totheclassificationsignaturecurrent(inthiscase,Class
3)intheVCLASSrange.Table3showsthepossibleclas-
sificationvalues.
Table3.ClassificationValues
CLASS
RESULT
Class0
NoClassSignaturePresent;TreatLikeClass3
Class1
3W
Class2
7W
Class3
13W
Class4
25.5W(Type2)
Ifclassificationisenabled,theportwillclassifythePD
immediatelyafterasuccessfuldetectioncycleinsemi-auto
orautomodes,orwhencommandedtoinmanualmode.It
measuresthePDclassificationsignaturebyapplying18V
for12ms(bothvaluestypical)totheportviatheOUT
npin
andmeasuringtheresultingcurrent;itthenreportsthe
discoveredclassintheportstatusregister.IftheLTC4266
wasresetwiththeAUTOpinhighandtheportisinauto
mode,itwilladditionallyusetheclassificationresulttoset
theICUTandILIMthresholds.SeethePower-OnResetand
theAUTO/MIDPinsectionformoreinformation.
Theclassificationcircuitryisdisabledwhentheportis
initiallypoweredupwiththeAUTOpinlow,inshutdown
mode, or when the corresponding class enable bit is
cleared.
802.3at2-EventClassification
The802.3atspecdefinestwomethodsofclassifyinga
Type2PD.
OnemethodaddsextrafieldstotheEthernetLLDPdata
protocol;althoughtheLTC4266iscompatiblewiththis
classification method, it cannot perform classification
directly since it doesn’t have access to the data path.
LLDPclassificationrequiresthePSEtopowerthePDas
astandard802.3af(Type1)device.Itthenwaitsforthe
hosttoperformLLDPcommunicationwiththePDand
updatethePSEportdata.TheLTC4266supportschang-
ingtheILIMandICUTlevelsonthefly,allowingthehost
tocompleteLLDPclassification.
Thesecond802.3atclassificationmethod,knownas2-
eventclassificationorping-pong,isfullysupportedbythe
LTC4266.AType2PDthatisrequestingmorethan13W
willindicateClass4duringnormal802.3afclassification.
IftheLTC4266seesClass4,itforcestheporttoaspeci-
fiedlowervoltage(calledthemarkvoltage,typically9V),
pausesbriefly,andthenre-runsclassificationtoverifythe
Class4reading(Figure1).Italsosetsabitinthehigh
VOLTAGE (VCLASS)
0
CURRENT
(mA)
60
50
40
30
20
10
0
5
10
15
20
4266 F13
25
TYPICAL
CLASS 3
PD LOAD
LINE
48mA
33mA
PSE LOAD LINE
23mA
14.5mA
6.5mA
CLASS 4
CLASS 2
CLASS 1
CLASS 0
CLASS 3
OVER
CURRENT
Figure13.PDClassification
相關PDF資料
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相關代理商/技術參數
參數描述
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:- 標準包裝: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 供應商設備封裝: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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