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参数资料
| 型号： | LTC4266AIUHF-3#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： | 19/28页 |
| 文件大小： | 325K |
| 代理商： | LTC4266AIUHF-3#TRPBF |
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LTC4266A/LTC4266C
26
4266acf
External MOSFET
CarefulselectionofthepowerMOSFETiscriticaltosystem
reliability. LTC recommends either Fairchild IRFM120A,
FDT3612, FDMC3612 or Philips PHT6NQ10T for their
proven reliability in Type 1 and Type 2 PSE applications.
Non-standard applications that provide more current than
the 850mA IEEE maximum may require heat sinking and
other MOSFET design considerations. Contact LTC Ap-
plications before using a MOSFET other than one of these
recommended parts.
Sense Resistor
TheLTC4266A/LTC4266Cisdesignedtouseeither0.5Ωor
0.25Ω current sense resistors. For new designs 0.25Ω is
recommended to reduce power dissipation; the 0.5Ω op-
tion is intended for existing systems where the LTC4266A/
LTC4266Cisusedasadrop-inreplacementfortheLTC4258
or LTC4259A. The lower sense resistor values reduce
heat dissipation. Four commonly available 1Ω resistors
(0402 or larger package size) can be used in parallel in
place of a single 0.25Ω resistor. In order to meet the ICUT
and ILIM accuracy required by the IEEE specification, the
sense resistors should have ±1% tolerance or better, and
no more than ±200ppm/°C temperature coefficient.
Port Output Cap
Each port requires a 0.22μF cap across its outputs to
keep the LTC4266A/LTC4266C stable while in current limit
during startup or overload. Common ceramic capacitors
often have significant voltage coefficients; this means the
capacitance is reduced as the applied voltage increases.
To minimize this problem, X7R ceramic capacitors rated
for at least 100V are recommended.
ESD/Cable Discharge Protection
EthernetportscanbesubjecttosignificantESDeventswhen
long data cables, each potentially charged to thousands
of volts, are plugged into the low impedance of the RJ45
jack. To protect against damage, each port requires a pair
of clamp diodes; one to AGND and one to VEE (Figure 10).
An additional surge suppressor is required for each
LTC4266A/LTC4266C chip from VEE to AGND. The diodes
at the ports steer harmful surges into the supply rails,
where they are absorbed by the surge suppressor and the
VEE bypass capacitance. The surge suppressor has the
additional benefit of protecting the LTC4266A/LTC4266C
from transients on the VEE supply.
S1B diodes work well as port clamp diodes, and an
SMAJ58A or equivalent is recommended for the VEEsurge
suppressor.
LAYOUT GUIDELINES
Strict adherence to board layout, parts placement and
routing guidelines is critical for optimal current read-
ing accuracy, IEEE compliance, system robustness, and
thermal dissipation.
Power delivery above 25.5W imposes additional com-
ponent and layout restraints. Specifically MOSFET, sense
resistor and transformer selection is crucial to safe and
reliable system operation.
Contact LTC Applications to obtain a full set of layout
guidelines, example layouts and BOMs.
ApplicAtions inForMAtion
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4266AIUHF-4#PBF | 功能描述:IC CONTROLLER PSE QUAD 38-QFN RoHS:是 类别:集成电路 (IC) >> 接口 - 控制器 系列:- 标准包装:2,450 系列:- 控制器类型:SPI 总线至 I²C 总线桥接 接口:I²C，串行，SPI 电源电压:2.4 V ~ 3.6 V 电流 - 电源:11mA 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:24-VFQFN 裸露焊盘 供应商设备封装:24-HVQFN（4x4） 包装:托盘 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名称:935286452157SC18IS600IBSSC18IS600IBS-ND |
| LTC4266AIUHF-4#TRPBF | 功能描述:IC CONTROLLER PSE QUAD 38-QFN RoHS:是 类别:集成电路 (IC) >> 接口 - 控制器 系列:- 标准包装:2,450 系列:- 控制器类型:SPI 总线至 I²C 总线桥接 接口:I²C，串行，SPI 电源电压:2.4 V ~ 3.6 V 电流 - 电源:11mA 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:24-VFQFN 裸露焊盘 供应商设备封装:24-HVQFN（4x4） 包装:托盘 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名称:935286452157SC18IS600IBSSC18IS600IBS-ND |
| LTC4266C | 制造商:LINER 制造商全称:Linear Technology 功能描述:12-Port PoE/PoE+/LTPoE++ PSE Controller |
| LTC4266CGW#PBF | 制造商:Linear Technology 功能描述:POE Controller 25.5W 36-Pin SSOP 制造商:Linear Technology 功能描述:IC POE CONTROLLER 3.3V SSOP-36 制造商:Linear Technology 功能描述:IC QUAD POE CONTROLLER 3.3V 制造商:Linear Technology 功能描述:IC, POE CONTROLLER, 3.3V, SSOP-36; Input Voltage:3.3V; Supply Current:-2.4mA; UVLO:25V; Digital IC Case Style:SSOP; No. of Pins:36; Duty Cycle (%):60%; Frequency:1MHz; Operating Temperature Min:0C; Operating Temperature Max:70C ;RoHS Compliant: Yes |
| LTC4266CGW#TRPBF | 制造商:Linear Technology 功能描述:POE Controller 25.5W 36-Pin SSOP W |
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