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参数资料
| 型号： | LTC4274AIUHF-2#TRPBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 电源管理 |
| 英文描述： | POWER SUPPLY MANAGEMENT CKT, PQCC38 |
| 封装： | 7 X 5 MM, LEAD FREE, PLASTIC, MO-220WHKD, QFN-38 |
| 文件页数： | 7/28页 |
| 文件大小： | 313K |
| 代理商： | LTC4274AIUHF-2#TRPBF |
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LTC4274A/LTC4274C
15
4274acf
operAtion
Figure 10. Power over Ethernet System Diagram
LTC4274 Product Family
The LTC4274 is a third-generation quad PSE controller
that implements four PSE ports in either an end-point
or midspan design. Virtually all necessary circuitry is
included to implement an IEEE 802.3at compliant PSE
design, requiring only an external power MOSFET and
sense resistor; these minimize power loss compared to
alternative designs with an on-board MOSFET.
The LTC4274 comes in three grades which support dif-
ferent PD power levels.
TheA-gradeLTC4274extendsPoEpowerdeliverycapabili-
ties to LTPoE++ levels. LTPoE++ is a Linear Technology
proprietary specification allowing for the delivery of up to
90WtoLTPoE++compliantPDs.TheLTPoE++architecture
extendstheIEEEphysicalpowernegotiationtoinclude35W,
45W, 70W and 90W power levels. The A-grade LTC4274
also incorporates all B- and C-grade features.
The B-grade LTC4274 is a fully IEEE-compliant Type 2
PSE supporting autonomous detection, classification
and powering of Type 1 and Type 2 PDs. The B-grade
LTC4274 also incorporates all C-grade features. The
B-grade LTC4274 is marketed and numbered without the
B suffix for legacy reasons; the absence of power grade
suffix infers a B-grade part.
TheC-gradeLTC4274isafullyautonomous802.3atType1
PSE solution. Intended for use only in AUTO pin mode,
the C-grade chipset autonomously supports detection,
classification and powering of Type 1 PDs. As a Type 1
PSE, 2-event classification is prohibited and Class 4 PDs
are automatically treated as Class 0 PDs.
PoE Basics
Common Ethernet data connections consist of two or four
twisted pairs of copper wire (commonly known as CAT-5
cable), transformer-coupled at each end to avoid ground
loops. PoE systems take advantage of this coupling ar-
rangement by applying voltage between the center-taps
of the data transformers to transmit power from the PSE
to the PD without affecting data transmission. Figure 10
shows a high-level PoE system schematic.
To avoid damaging legacy data equipment that does not
expect to see DC voltage, the PoE spec defines a protocol
that determines when the PSE may apply and remove
power. Valid PDs are required to have a specific 25kΩ
common-mode resistance at their input. When such a PD
is connected to the cable, the PSE detects this signature
resistance and turns on the power. When the PD is later
disconnected, the PSE senses the open circuit and turns
power off. The PSE also turns off power in the event of a
current fault or short-circuit.
4274AC F10
S1B
SMAJ58A
58V
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
LTC4274A/
LTC4274C
DGND
AGND
I2C
3.3V
INTERRUPT
–54V
CAT 5
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
VIN
PWRGD
VOUT
LTC4265
GND
DC/DC
CONVERTER
5F ≤ CIN
≤ 300F
+
–
VOUT
GND
0.1F
100V
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4274AIUHF-3#PBF | 功能描述:IC CONTROLLER POE 38-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:119 系列:- 类型:热交换控制器 应用:通用型，PCI Express? 内部开关:无 电流限制:- 电源电压:3.3V，12V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:80-TQFP 供应商设备封装:80-TQFP（12x12） 包装:托盘 产品目录页面:1423 (CN2011-ZH PDF) |
| LTC4274AIUHF-3#TRPBF | 功能描述:IC CONTROLLER POE 38-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:119 系列:- 类型:热交换控制器 应用:通用型，PCI Express? 内部开关:无 电流限制:- 电源电压:3.3V，12V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:80-TQFP 供应商设备封装:80-TQFP（12x12） 包装:托盘 产品目录页面:1423 (CN2011-ZH PDF) |
| LTC4274AIUHF-4#PBF | 功能描述:IC CONTROLLER POE 38-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:119 系列:- 类型:热交换控制器 应用:通用型，PCI Express? 内部开关:无 电流限制:- 电源电压:3.3V，12V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:80-TQFP 供应商设备封装:80-TQFP（12x12） 包装:托盘 产品目录页面:1423 (CN2011-ZH PDF) |
| LTC4274AIUHF-4#TRPBF | 功能描述:IC CONTROLLER POE 38-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:119 系列:- 类型:热交换控制器 应用:通用型，PCI Express? 内部开关:无 电流限制:- 电源电压:3.3V，12V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:80-TQFP 供应商设备封装:80-TQFP（12x12） 包装:托盘 产品目录页面:1423 (CN2011-ZH PDF) |
| LTC4274C | 制造商:LINER 制造商全称:Linear Technology 功能描述:12-Port PoE/PoE+/LTPoE++ PSE Controller |
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