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Reference DesignAnalog

Analog LTC4269-1 PoE+ PD Controller and Synchronous Flyback Reference Design (DC1335B-B)

Reference design for a 5V, 4.5A PoE+ powered device using the LTC4269-1 controller, featuring isolated flyback topology and synchronous rectification.

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Overview

The DC1335B-B demonstration circuit is a high-power PoE+ (IEEE 802.3at) Powered Device (PD) interface and power supply featuring the LTC4269-1 controller. The board utilizes an isolated flyback topology with synchronous rectification to provide a regulated 5V output at currents up to 4.5A. It supports an input voltage range of 37V to 57V via PoE or 44V to 57V via an auxiliary wall adapter. The design features a two-stage filter for low differential mode emissions and achieves a typical efficiency of 91% at 50V input. The document includes performance specifications, setup instructions, thermal data, a comprehensive bill of materials, and full schematic diagrams.

Use Cases

  • High-power PoE PD systems
  • IP security cameras
  • Wireless access points
  • VoIP telephony
  • Industrial network equipment

Topics

LTC4269-1
PoE+
IEEE 802.3at
Powered Device
Synchronous Flyback
DC1335B-B
DC/DC Converter
Analog Devices
Linear Technology

Referenced Parts

FDS2582

Fairchild

MOSFET, N-CH, 150V, 4.1A, SO8

FDS8880

Fairchild

MOSFET, N-CH, 30-V, SO8

BSS63LT1

Onsemi

TRANSISTOR, PNP, SILICON POWER, SOT23, BSS63LT1

MMBT3904

Onsemi

TRANSISTOR, NPN, SILICON POWER, SOT23

MMBT3906

Onsemi

TRANSISTOR, PNP, SILICON POWER, SOT23

ETH1-230LB

Coilcraft

XFMR, POE PLUS, ETH1-230LD, COILCRAFT, ETH1-230LB

B1100-13-F

Diodes Inc.

DIODE, SCHOTTKY, 1A, SMA-DIODE

BAS21-7-F

Diodes Inc.

DIODE, FAST SWITCHING, SOT23

BAT54-7-F

Diodes Inc.

DIODE, SCHOTTKY, SOT23

S1B-13-F

Diodes Inc.

DIODE, 1A, PASSIVATED RECTIFIER

SMAJ58A-13-F

Diodes Inc.

DIODE, 58V, 400W, TVS, SMA-DIODE

LRC-LRF1206LF-01-R033-F

IRC

RES., CHIP, 0.033Ω, 1/8W, 1%, 1206

LTC4269IDKD-1

Linear Technology

IC, LTC4269IDKD-1, DFN32

GRM21BR71C105KA01

Murata

CAP., X7R, 1μF, 16V, 0805

GRM31CR60J226KE19

Murata

CAP., X5R, 22μF, 6.3V, 1206

GRM32ER72A225KA01

Murata

CAP., X7R, 2.2μF, 100V, 1210

PS2801-1-F3--L-A

NEC

IC, OPTOCOUPLERS PS2801-1-L, NEC, PS2801-1-F3--L-A

PDZ36B

NXP

DIODE, SMT ZENER, 36V, 400mW

ESVB21C106M

Neo Capacitor

CAP., TANT, 10μF, 16V, B2

PSLB20J107M(45

Neo Capacitor

CAP., TANT, 100μF, 6.3V, 3528

SS-6488-NF-K1

Stewart Connector Systems

CONN., RJ-45 RIGHT ANGLE, RJ45

CRCW060310K0JKEA

Vishay

RES., CHIP, 10k, 1/16W, 5%, 0603

CRCW060312K0JKEA

Vishay

RES., CHIP, 12k, 1/16W, 5%, 0603

CRCW060320K0JKEA

Vishay

RES., CHIP, 20k, 1/16W, 5%, 0603

CRCW060324K0JKEA

Vishay

RES., CHIP, 24k, 1/16W, 5%, 0603

8834

Keystone

STAND-OFF, NYLON (SNAP ON), 0.625” TALL, KEYSTONE, 8834

D2-9

Diodes

and signal pairs. Schottky diodes (D2-9) are used at the

SOT23

Diodes

17 2 D11, D16 DIODE, FAST SWITCHING, SOT23 DIODES INC., BAS21-7-F

SOT23

Diodes

18 1 D14 DIODE, SCHOTTKY, SOT23 DIODES INC., BAT54-7-F

400mW

NXP

8 1 D13 DIODE, SMT ZENER, 36V, 400mW NXP, PDZ36B