LT4295IUFD#TRPBF - 802.3bt PoE PD Interface Controller | Analog Devices
MPN: LT4295IUFDTRPBF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.11 | $4.11 |
| 10 | $3.7 | $37.00 |
| 100 | $3.27 | $327.00 |
| 500 | $3.05 | $1,525.00 |
| 1,000 | $3.27 | $3,270.00 |
LT4295IUFDTRPBF Overview
A PoE PD interface controller is the power-management front end of a powered device such as a security camera, wireless access point, or IP phone. It sits at the top of the PoE power hierarchy: IEEE 802.3 standard -> Power Sourcing Equipment (PSE) -> Powered Device interface -> DC-DC converter. The PD interface performs detection, classification, inrush current limiting, and load disconnect per the IEEE 802.3af (PoE), 802.3at (PoE+), and 802.3bt (PoE++) specifications, then hands off regulated power to the switching regulator stage.
Key features of the LT4295 include full IEEE 802.3bt (Type 3/Type 4, up to 71.3W single-signature) compliance, an integrated forward/flyback controller that eliminates a second controller IC, and support for external low-RDS(on) hot-swap N-channel MOSFETs to minimize power loss. Auxiliary input sensing via a simple resistor divider on the AUX pin allows seamless wall-adapter fallback, and compatibility with LT4320/LT4321 ideal diode bridge controllers extends end-to-end efficiency by eliminating diode bridge drops and costly heatsinks.
Technically, the part integrates detection/classification state machines, a hot-swap FET gate driver, and a current-mode switching regulator controller with current-threshold control (ITHB) and feedback (FB31) pins for flyback transformer regulation. It primarily targets single-signature PD topologies but can be deployed in dual-signature designs in consultation with Analog Devices applications engineering.
Typical applications include 802.3bt IP cameras, 60W/71W wireless access points, VoIP phones, PoE LED lighting, and industrial network nodes requiring wall-adapter auxiliary power.
A key design consideration: the forward/flyback controller uses an external primary FET, so peak current set by ITHB and transformer design determine delivered power; follow the RFFSDLY (5.23k ohm typ.) fault-timing guidance in the datasheet.
This page synthesizes distributor pricing, same-family drop-in alternatives, and practical design notes beyond what the manufacturer datasheet alone provides.
Drop-in alternatives for LT4295IUFDTRPBF — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LT4276IUFD#TRPBF
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LT4275IUFD#TRPBF
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LT4293IUFD#TRPBF
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LT4295IUFD#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LT4295IUFDTRPBF Specifications
| Function | IEEE 802.3bt PoE PD Interface with Forward/Flyback Controller |
| PoE Standard Support | IEEE 802.3af (PoE), 802.3at (PoE+), 802.3bt (PoE++) |
| Channels | 1 |
| Input Voltage Rating | 60 V |
| Maximum Power Class | 71.3 W (802.3bt single-signature) |
| Switching Regulator Topology | Forward / Flyback |
| Hot-Swap MOSFET | External N-channel, low RDS(on) |
| Ideal Diode Bridge Support | LT4320 / LT4321 compatible |
| Auxiliary Input Sensing | Yes (resistor divider on AUX pin) |
| RFFSDLY Fault Timing Resistor | 5.23 k ohm to GND (typical) |
| Package | 28-QFN (4x5 mm) with exposed pad (UFD) |
| Mounting Type | Surface Mount |
| Operating Temperature Grade | Industrial (I grade, -40C to +125C junction) |
| RoHS Status | Compliant (PBF suffix) |
| Packaging | Tape and Reel (#TRPBF suffix) |
| 1ku List Price | From $3.27 (as of 2026-10-19) |
LT4295IUFDTRPBF 28-qfn (4x5 mm) with exposed pad (ufd) Pin Configuration Guide
Pin configuration for LT4295IUFDTRPBF (28-qfn (4x5 mm) with exposed pad (ufd) package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for LT4295IUFDTRPBF.
Refer to the datasheet for full pin configuration.
Typical Applications
LT4295IUFDTRPBF is suitable for 6 applications: 802.3bt IP Security Cameras, Wireless Access Points, PoE LED Lighting, VoIP and Video Phones, Industrial Network Nodes and Sensors, 5G Small Cells and Network Edge Equipment.
802.3bt IP Security Cameras
The LT4295's 802.3bt compliance delivers up to 71.3W from a single Ethernet cable, enough for PTZ cameras with heaters, IR illuminators, and edge-AI analytics that exceed the 25.5W PoE+ budget. Its integrated forward/flyback controller converts the 48V PoE rail directly to camera system voltages, eliminating a separate controller IC and shrinking the power section. The AUX pin enables wall-adapter fallback where PoE is unavailable, and LT4321 ideal-diode bridge support removes bridge diode losses, reducing internal heat in sealed camera housings - a critical benefit for outdoor reliability.
Recommended
Wireless Access Points
Multi-radio 802.11ax/be access points routinely draw 40-70W, exactly the envelope of 802.3bt Type 3/4 power that the LT4295 negotiates and delivers. The PD interface performs bt classification automatically, while the integrated forward/flyback controller steps the -48V rail down to the radio and SoC supplies with current-mode control. External low-RDS(on) hot-swap MOSFET drive keeps series losses in the milliohm range, preserving efficiency end-to-end. The 4x5 mm QFN with exposed pad suits the dense, thermally constrained layouts of ceiling-mounted APs where airflow is minimal.
Recommended
PoE LED Lighting
PoE LED luminaires combine data and power on one cable, and the LT4295 provides the 71.3W budget needed for high-output fixtures while its forward controller can directly drive LED string power stages. The 60V input rating comfortably exceeds the 48V PoE rail with transient margin per IEEE 802.3bt requirements. Inrush limiting and IEEE-compliant disconnect protect both the luminaire and the PoE switch port. The AUX pin sensing allows hybrid fixtures that run from PoE or an AC adapter, and the industrial temperature grade supports enclosed luminaire environments up to 125C junction.
Recommended
VoIP and Video Phones
Enterprise IP phones must power displays, speaker amplifiers, and Gigabit switch ICs from the Ethernet cable; the LT4295 covers both legacy 802.3af (13W) and modern 802.3bt (up to 71.3W) classes, letting one platform serve multiple phone tiers. The PD interface's detection and classification fully comply with IEEE 802.3af/at/bt, ensuring interoperability across PoE switch vendors. Its forward/flyback controller generates the phone's core rails from the 48V input, and external FET selection lets designers trade BOM cost against efficiency. Demonstration Circuit 2476A provides a proven reference design to shorten certification cycles.
Recommended
Industrial Network Nodes and Sensors
Factory-floor Ethernet nodes - gateways, IIoT sensor hubs, and edge controllers - benefit from the LT4295's wide 60V rating, which absorbs PoE rail transients and surge conditions typical of industrial cabling. The AUX resistor-divider sensing supports local 24V auxiliary supplies with clean handover to PoE, and the external hot-swap MOSFET provides robust inrush and fault protection for downstream loads. Ideal-diode bridge support via LT4321 removes rectification heat in sealed enclosures. The industrial temperature grade (-40C to +125C junction) matches harsh-environment deployment requirements without derating complexity.
Recommended
5G Small Cells and Network Edge Equipment
5G small cells and street-level edge devices frequently deploy where only one Ethernet cable is available, making 802.3bt power delivery essential. The LT4295's 71.3W capability supports radio unit power budgets, and its integrated forward/flyback controller efficiently generates the multiple rails (RF PA, baseband, backhaul) from the single PoE input. Flyback mode allows isolated topologies where safety isolation is required between the PoE input and radio circuitry. The compact 4x5 mm QFN and external-FET architecture let designers size the power stage precisely to the small cell's thermal budget.
Recommended
Recommended Products Summary
Engineering reference data for LT4295IUFDTRPBF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LT4276IUFD#TRPBF | LT4275IUFD#TRPBF | LT4293IUFD#TRPBF | LT4295IUFD#PBF |
|---|---|---|---|---|---|
| Package | 28-QFN (4x5 mm) UFD | 28-QFN (4x5 mm) UFD - same | 28-QFN (4x5 mm) UFD - same | 28-QFN (4x5 mm) UFD - same | 28-QFN (4x5 mm) UFD - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| PoE Standard Support | 802.3af / at / bt | 802.3af / at | 802.3af / at | 802.3af / at / bt | 802.3af / at / bt - identical |
| Integrated Switching Controller | Forward / Flyback | Flyback | Flyback | Flyback | Forward / Flyback - identical |
| Packaging / Lifecycle | Tape & Reel, active, recommended for new designs | Tape & Reel, active | Tape & Reel, active | Tape & Reel, active | Tube / cut tape, active - identical die |
Key Differentiators
- 802.3bt power class with integrated forward/flyback controller (vs LT4276IUFD#TRPBF)
- Same-die packaging flexibility (vs LT4295IUFD#PBF)
- Ideal-diode bridge integration path (vs LT4293IUFD#TRPBF)
Design Notes
Use an external, low-RDS(on) N-channel MOSFET for the hot-swap path as the datasheet specifies - the LT4295 drives it externally to minimize series loss at 71.3W loads. Pair with an LT4320 or LT4321 ideal diode bridge instead of Schottky bridges to eliminate roughly 2x diode drops (about 1.4W saved at 2A input current), often removing heatsink requirements entirely. Set RFFSDLY to 5.23k ohm to GND per the datasheet typical application for correct fault timing.
Keep the hot-swap MOSFET, sense resistor, and transformer primary loop tight to limit switching-node ringing in the forward/flyback stage. The ITHB pin (pin 13) sets peak primary current via the current-sense comparator - route its sense lines as a Kelvin connection to the sense resistor. FB31 (pin 14) senses the flyback tertiary winding; keep this divider close to the pin to avoid noise-induced regulation errors. Exposed pad must be soldered to a solid ground pour for thermal and EMI performance.
The LT4295 primarily targets single-signature PD topologies per the datasheet; deploying in dual-signature 802.3bt designs requires consultation with Analog Devices applications before finalizing the design. Do not exceed the 60V rating on VPORT paths - PoE transients demand adequate bridge and clamp selection. For auxiliary power, size the AUX resistor divider so wall-adapter switchover thresholds comply with the IEEE disconnect requirements, avoiding oscillation between sources.
IEEE 802.3bt compliance testing includes conducted emissions on the Ethernet pair; use a common-mode choke and follow the DC2476A demonstration circuit (IEEE 802.3bt Draft 2.2 compliant PD with LT4295 and LT4321) layout as the reference for magnetics placement and shielding. Pre-compliance testing early in the layout phase avoids costly respins around the QFN and transformer area.
Compliance Information
PBF suffix denotes lead-free per Analog Devices convention; distributor listings (DigiKey, Mouser) categorize the part as RoHS-compliant. REACH, halogen-free, and conflict-minerals status should be confirmed via the Analog Devices product page compliance documents.
