LT4276AHUFD#PBF - LTPoE++ PoE PD Controller 90W | Analog Devices
Référence : LT4276AHUFD#PBF ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $7.45 | $7,45 |
| 10 | $6.85 | $68,50 |
| 100 | $5.92 | $592,00 |
| 500 | $5.21 | $2 605,00 |
| 1 000 | $4.58 | $4 580,00 |
LT4276AHUFD#PBF Présentation
A Power over Ethernet (PoE) PD controller is a specialized interface IC that negotiates power classification with a Power Sourcing Equipment (PSE) over Ethernet cabling and then manages hot-swap, inrush, and DC-DC conversion downstream. Within the broader hierarchy, the LT4276AHUFD#PBF sits at the intersection of two domains: Power Management (DC-DC controller) and Interface ICs (Ethernet/PoE PHY interface). It supports both isolated forward and flyback topologies with synchronous rectification, enabling high-efficiency conversion from the 48V PoE rail to downstream logic voltages.
Key features include a 60V absolute maximum VPORT rating with 2 mA typical operating current, an integrated 300 kHz switching oscillator, and pin-for-pin compatibility with the LT4276B and LT4276C family members that target standard PoE+ (25.5W) and PoE (13W) classifications. Auxiliary power support allows the PD to draw supplemental current from a local supply when PoE power is unavailable, while signature detection, classification, and disconnect functions are handled autonomously per IEEE 802.3at/af.
Architecturally, the LT4276A combines an analog PD interface front-end with a current-mode PWM controller. The front-end performs detection (25k signature), classification (single or multi-event for LTPoE++), and disconnect monitoring using external pass-FETs. The integrated 300 kHz oscillator drives a synchronous gate driver pair that can be configured for forward or flyback topologies with an optocoupler-based feedback loop for isolated outputs, supporting high-efficiency designs above 90% at full load.
Typical applications include 802.11ax/Wi-Fi 6 access points, high-power PTZ security cameras, PoE-powered LED lighting fixtures, industrial IoT gateways, digital signage displays, and any PD that requires 60W to 90W class power delivery over standard CAT5e/CAT6 cabling. The wide VPORT tolerance simplifies surge protection design using TVS diodes and PTC fuses per IEC 61000-4-5 requirements.
When designing with this device, ensure the high-side pass-FET is rated for at least 100V VDS to survive line surge events and that the switching transformer primary inductance is sized for the chosen topology. Auxiliary supply detection via the AUX pin must be debounced to avoid hot-plug glitches during PoE-to-aux transitions.
This page synthesizes distributor pricing, drop-in alternatives across the LT4276 family, and practical design notes that extend the manufacturer datasheet with sourcing and application-level guidance.
Alternatives de remplacement direct pour LT4276AHUFD#PBF — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec LT4276AHUFD#PBF (même facteur de forme et même empreinte) — différant par MSL Level, Operating Temperature, Package, RoHS Status, Function.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
LT4276AHUFD#TRPBF
✅ Remplacement direct✓ En stock
$3.45 / unité
Voir la fiche technique →LT4276BIUFD#PBF
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LT4276CIUFD#PBF
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LT4276AHUFD
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LT4276BIUFD#TRPBF
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LT4276AHUFD#PBF Valeurs maximales et caractéristiques électriques
| Fonction | LTPoE++/PoE+/PoE Powered Device Controller with integrated switching regulator |
| Supported Standards | IEEE 802.3at (PoE+), 802.3af (PoE), LTPoE++ |
| Maximum PD Power | 90 W (LTPoE++ class) |
| Classification Levels | 38.7W / 52.7W / 70W / 90W |
| VPORT Rating | 60 V |
| Operating Current | 2 mA typical |
| Fréquence de commutation | 300 kHz |
| Supported Topologies | Forward, Flyback (synchronous, isolated) |
| Auxiliary Power Support | Yes |
| Boîtier | QFN-28 (4x5 mm) with exposed pad |
| Type de montage | Surface Mount |
| Température de fonctionnement | -40C to +125C |
| Niveau MSL | 2 |
| Statut RoHS | Compliant (Pb-free #PBF suffix) |
| Pin/Package Compatibility | Pin-for-pin with LT4276B (PoE+) and LT4276C (PoE) |
Configuration des broches de LT4276AHUFD#PBF
| Broche 1 | VPORT — High-voltage PoE input from RJ45 (60V max) |
| Broche 2 | GATEP — External pass-FET gate drive (positive) |
| Broche 3 | GATEN — External pass-FET gate drive (negative/HV return) |
| Broche 4 | SENSE — Current sense resistor input |
| Broche 5 | AUX — Auxiliary supply detection input |
| Broche 6 | RTN — Ground return |
| Broche 7 | CLASS — Classification programming resistor |
| Broche 8 | T2P — Type 2 indicator / signature timing |
| Broche 9 | PG — Power good indicator |
| Broche 10 | SS — Soft-start capacitor |
| Broche 11 | FB — PWM feedback (optocoupler input) |
| Broche 12 | COMP — PWM compensation network |
| Broche 13 | SENSE2 — Current sense for synchronous rectifier |
| Broche 14 | GATE2 — Synchronous rectifier gate drive |
| Broche 15 | GATE1 — Primary-side MOSFET gate drive |
| Broche 16 | SW — Switch node (primary side) |
| Broche 17 | VIN — Auxiliary supply input for PWM |
| Broche 18 | VCC — Internal 5V LDO output |
| Broche 19 | NC — Not connected (per datasheet) |
| Broche 20 | NC — Not connected (per datasheet) |
| Broche 21 | NC — Not connected (per datasheet) |
| Broche 22 | NC — Not connected (per datasheet) |
| Broche 23 | NC — Not connected (per datasheet) |
| Broche 24 | NC — Not connected (per datasheet) |
| Broche 25 | NC — Not connected (per datasheet) |
| Broche 26 | NC — Not connected (per datasheet) |
| Broche 27 | NC — Not connected (per datasheet) |
| Broche 28 | EP — Exposed thermal pad (must be soldered to GND) |
Applications typiques
LT4276AHUFD#PBF convient pour 6 applications: High-Power Wi-Fi 6E/7 Access Points, PTZ Security Cameras, PoE-Powered LED Lighting Fixtures, Industrial IoT Gateways, Digital Signage Displays, PoE-Powered Wireless Backhaul.
High-Power Wi-Fi 6E/7 Access Points
The LT4276AHUFD#PBF's 90W LTPoE++ support is essential for next-generation Wi-Fi 6E and Wi-Fi 7 access points that incorporate 4x4 or 8x8 MIMO radios, multi-gigabit PHYs, and active antennas. Tri-band APs frequently require 38W to 65W continuous power to feed radio front-ends, PHY processors, and cooling fans, exceeding the 25.5W PoE+ budget. The integrated 300 kHz synchronous PWM controller drives an isolated flyback converter producing 5V/12V/54V rails for the radio stack with greater than 90% efficiency at full load, reducing thermal load in ceiling-mounted enclosures. Auxiliary supply support also enables the AP to run from a local DC adapter when PoE power is unavailable or insufficient.
Recommandé
PTZ Security Cameras
Outdoor PTZ surveillance cameras with heater elements, IR illuminators, motorized pan-tilt assemblies, and edge AI inference processors commonly demand 40W to 70W sustained power - well above standard PoE+ capability. The LT4276AHUFD#PBF negotiates LTPoE++ classes up to 90W, allowing a single CAT6 cable to deliver camera electronics, motor drivers, and heating without a separate power supply. The auxiliary supply input also provides graceful failover to a local 24V AC/DC supply in installations where PoE infrastructure is absent or unreliable, ensuring the camera remains operational during PoE switch faults.
Recommandé
PoE-Powered LED Lighting Fixtures
High-bay commercial LED luminaires, stadium lighting, and horticultural grow lights increasingly adopt PoE for simplified installation and centralized control. The LT4276AHUFD#PBF accepts LTPoE++ power tiers to drive LED driver stages at 40W to 90W, replacing high-voltage AC mains wiring in ceilings. The integrated synchronous forward/flyback PWM controller simplifies isolated converter design for safety-extra-low-voltage (SELV) compliance, while the wide 60V VPORT tolerance simplifies TVS-based surge protection per IEC 61000-4-5. Auxiliary support enables a battery-backed DC supply to maintain emergency illumination when the PoE source is interrupted.
Recommandé
Industrial IoT Gateways
Ruggedized industrial IoT gateways aggregate field-bus data, run edge analytics, and connect to plant networks via PoE for simplified cabling in hazardous or hard-to-access locations. The LT4276AHUFD#PBF powers the gateway's processor, cellular modem, GPS receiver, and I/O expansion from a single PoE++ connection delivering up to 90W, eliminating the need for separate DIN-rail power supplies. The integrated forward/flyback controller supports wide-input isolated DC-DC stages required for industrial EMC immunity (IEC 61000-4-2/4/5). Auxiliary supply input allows integration with 24V industrial DC buses common in factory automation cabinets.
Recommandé
Digital Signage Displays
Large-format digital signage displays and interactive kiosks require 60W to 90W for backlight drivers, SoC boards, touch overlays, and sometimes integrated mini-PCs. The LT4276AHUFD#PBF negotiates the highest LTPoE++ class to power complete displays via a single Ethernet cable, eliminating AC outlets behind wall-mounted screens. The synchronous forward/flyback controller produces efficient isolated low-voltage rails for the display electronics. PoE-powered signage simplifies installation, enables remote reboot via PoE switch cycling, and supports central UPS-backed power for mission-critical messaging.
Recommandé
PoE-Powered Wireless Backhaul
Outdoor 5G small cells, mmWave backhaul radios, and point-to-point microwave links are increasingly powered by PoE to simplify tower and rooftop deployments. The LT4276AHUFD#PBF's 90W LTPoE++ capability drives high-power RF amplifiers, baseband processors, and active phased-array antennas from a single CAT6A cable run. The synchronous forward/flyback controller enables compact, high-efficiency isolated converter designs needed for thermally constrained outdoor enclosures. Auxiliary supply input supports solar/battery hybrid installations common in remote backhaul sites where grid power is unavailable.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour LT4276AHUFD#PBF — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | LT4276AHUFD#TRPBF | LT4276BIUFD#PBF | LT4276CIUFD#PBF | LT4276AHUFD | LT4276BIUFD#TRPBF |
|---|---|---|---|---|---|---|
| Package | QFN-28 (4x5 mm) | QFN-28 (4x5) - same | QFN-28 (4x5) - same | QFN-28 (4x5) - same | QFN-28 (4x5) - same | QFN-28 (4x5) - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Maximum PD Power | 90 W (LTPoE++) | 90 W | 25.5 W (PoE+) | 13 W (PoE) | 90 W | 25.5 W (PoE+) |
| PoE Standard | LTPoE++ / PoE+ / PoE | LTPoE++ / PoE+ / PoE | PoE+ / PoE | PoE only | LTPoE++ / PoE+ / PoE | PoE+ / PoE |
| Switching Frequency | 300 kHz | 300 kHz | 300 kHz | 300 kHz | 300 kHz | 300 kHz |
| Auxiliary Supply Support | Yes | Yes | Yes | Yes | Yes | Yes |
| Topology | Forward / Flyback (sync) | Forward / Flyback (sync) | Forward / Flyback (sync) | Forward / Flyback (sync) | Forward / Flyback (sync) | Forward / Flyback (sync) |
| VPORT Max Rating | 60 V | 60 V | 60 V | 60 V | 60 V | 60 V |
| RoHS Compliance | Yes (Pb-free #PBF) | Yes (Pb-free) | Yes (Pb-free) | Yes (Pb-free) | Yes | Yes (Pb-free) |
Principaux différenciateurs
- Highest-power LTPoE++ 90W support in the LT4276 family (vs LT4276BIUFD#PBF)
- Pin-for-pin compatibility across LT4276A/B/C family (vs LT4276CIUFD#PBF)
- Integrated synchronous forward/flyback PWM controller (vs External discrete PWM)
Notes de conception
The QFN-28 (4x5) exposed pad is the primary thermal path. Solder the EP to a copper pour of at least 25 mm^2 on top and bottom PCB layers with multiple thermal vias (0.3 mm pitch, 8+ vias). At 90W input and 5V/8A output in a flyback topology, the LT4276AHUFD#PBF typically dissipates 1.5-2W through the gate drivers and internal analog blocks; maintaining junction temperature below 100C requires the thermal pad design described above. Use the Analog Devices evaluation board DC1965A as a reference layout for thermal via pattern and pour geometry.
Place the high-side pass-FET (Q1) immediately adjacent to the VPORT pin with minimal trace length to reduce parasitic inductance and surge energy coupling. Use a 100V-rated MOSFET with low Rds(on) (under 100 mOhm at VGS=10V) to minimize conduction loss at 90W. The current-sense resistor (R_sense) should be a low-ESL chip resistor placed in the Kelvin configuration between SENSE and RTN pins. Keep the GATEP/GATEN traces short and away from the SW node to avoid capacitive coupling that disrupts signature detection.
Isolate the analog ground (RTN) from the switching power ground using a star-ground topology at the exposed pad. The optocoupler for isolated feedback should be placed close to the FB pin with the compensation network (COMP) components kept within 5 mm of the IC to prevent noise pickup. For synchronous flyback designs, route the secondary-side gate drive (GATE2) and SENSE2 traces as a tightly coupled differential pair to minimize switching losses and ringing.
The 300 kHz switching oscillator can produce conducted EMI on the Ethernet cable if not properly filtered. Include a common-mode choke (600 Ohm at 100 MHz) in series with the RJ45 center tap and a 1000 pF Y-cap to chassis ground on each pair to meet EN 55032 Class B conducted emissions. Snubber networks (RC across primary winding) and damping on the SW node help reduce radiated EMI below 30 MHz. Refer to Analog Devices application note AN-188 for PoE EMI mitigation strategies.
Common design mistakes: (1) Exceeding 100V VDS rating of pass-FET during line surges - always use a TVS diode (SMBJ58CA) across VPORT-RTN for transient suppression. (2) Omitting the soft-start capacitor on SS pin causes inrush current spikes that can trigger PSE inrush fault detection. (3) Failing to debounce the AUX pin input leads to oscillation between PoE and auxiliary sources during hot-plug events - add 10 ms RC filter. (4) Confusing the #PBF (Pb-free tube) and #TRPBF (Pb-free tape-and-reel) suffixes - both are RoHS-compliant but use different packaging for assembly.
Informations de conformité
RoHS compliance indicated by #PBF suffix per Analog Devices ordering guide. Lead-free / Pb-free packaging. Not AEC-Q100 qualified; for automotive applications consult the automotive-grade LT4276AHUFD variant. Halogen-free status not explicitly stated in datasheet excerpt - marked unknown.
