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reference designLT4276A

Analog Devices LT4276A

LTPoE++/PoE+/PoE PD Forward/Flyback Controller

Overview

TopologyForward Converter
Input voltage37-57 V
Switching frequency200-223 kHz
Output 112 V / 7 A
IC revisionA

Description

The LT®4276 is a pin-for-pin compatible family of IEEE 802.3 and LTPoE++ Powered Device (PD) controllers. It includes an isolated switching regulator controller capable of synchronous operation in both forward and flyback topologies with auxiliary power support.

The LT4276A employs the LTPoE++ classification scheme, receiving 38.7W, 52.7W, 70W or 90W of power at the PD RJ45 connector, and is backwards compatible with IEEE 802.3. The LT4276B is a fully 802.3at compliant, 25.5W Type 2 (PoE+) PD. The LT4276C is a fully 802.3af compliant, 13W Type 1 (PoE) PD.

The LT4276 supports both forward and flyback power supply topologies, configurable for a wide range of PoE applications. The flyback topology supports No-Opto feedback. Auxiliary input voltage can be accurately sensed with just a resistor divider connected to the AUX pin.

The LT4276 utilizes an external, low RDS(ON) N-channel MOSFET for the Hot Swap function, maximizing power delivery and efficiency, reducing heat dissipation, and easing the thermal design.

Features

  • IEEE802.3af/at and LTPoE++™ 90W Powered Device (PD) with Forward/Flyback Controller
  • LT4276A Supports All of the Following Standards:
  • LTPoE++ 38.7W, 52.7W, 70W and 90W
  • IEEE 802.3at 25.5W Compliant
  • IEEE 802.3af up to 13W Compliant
  • LT4276B is IEEE 802.3at/af Compliant
  • LT4276C is IEEE 802.3af Compliant
  • Superior Surge Protection (100V Absolute Maximum)
  • Wide Junction Temperature Range (–40°C to 125°C)
  • Auxiliary Power Support as Low as 9V
  • No Opto-Isolator Required for Flyback Operation
  • External Hot Swap™ N-Channel MOSFET for Lowest Power Dissipation and Highest System Efficiency

  • 94% End-to-End Efficiency with LT4321 Ideal Bridge

  • Available in a 28-Lead 4mm × 5mm QFN Package

Typical applications

  • Outdoor Security Camera Equipment
  • Commercial and Public Information Displays
  • High Power Wireless Data Systems
  • High Temperature Applications

More information

Products

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Order Code
Data­sheet
Simu­lation
Downloads
Status
Product series
IRP,40K(A)
ISAT,10%(A)
ISAT,30%(A)
RDC(mΩ)
fres(MHz)
Material
Qty.
Data rate
Ports
PoE
Improved CMRR
Operating Temperature
VT(V (RMS))
Mount
L(µH)
SamplesAvailability & Sample
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744314650
SPECWE-HCI SMT Flat Wire High Current Inductor, 6.6 A, 2 A

PCN pending

Due to a pending PCN, a modification of the component will be implemented soon. Please find the PCN below. If you have further questions please get in contact with our sales staff.

Simu­lation
Availability
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Downloads9 files

Status Activei| Production is active. Expected lifetime: >10 years.
Product seriesWE-HCI SMT Flat Wire High Current Inductor
Performance Rated Current6.6 A
Saturation Current @ 10%2 A
Saturation Current @ 30%6 A
DC Resistance21.5 mΩ
Self Resonant Frequency50 MHz
MaterialSuperflux 
Packaging Unit1000 
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–
–
–
Operating Temperature -40 °C up to +150 °C
–
MountSMT 
Inductance6.5 µH
–Check availability
749022016
SPECWE-LAN LAN Transformer, –, –
Simu­lation
Availability
–
Downloads4 files

Status Activei| Production is active. Expected lifetime: >10 years.
Product seriesWE-LAN LAN Transformer
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–
–
–
–
–
–
Data rate1000BASE-T 
Ports1 
PoEPoE+ (up to 1150 mA) 
Improved Common Mode RejectionNo 
Operating Temperature 0 °C up to +70 °C
Insulation Test Voltage1500 V (RMS)
MountSMT 
Inductance350 µH
–Check availability