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Analog Devices Inc. LT4294IMS#PBF
- Part No.:
- LT4294IMS#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT4294IMS#PBF.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:350
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Product details
Overview
LT4294IMS#PBF from Analog Devices is an IEEE 802.3af/at/bt-compliant single-signature powered device (PD) interface controller in a 10-lead MSOP package, supporting up to 71.3W input power, featuring 5-event classification sensing, integrated signature resistor (24.4 kΩ), and auxiliary power override down to 9V. It controls an external N-channel hot-swap MOSFET for high-efficiency PoE power delivery in outdoor security cameras and commercial displays.
For engineers reviewing the LT4294IMS#PBF datasheet, LT4294IMS#PBF pinout, LT4294IMS#PBF application, or LT4294IMS#PBF equivalent, this page delivers verified technical context, real-world timing behavior (T2P frequency: 690–990 Hz), thermal protection (–40°C to 85°C operating range), and migration guidance from LTPoE++ PDs via pin-compatible design with LT4275 family controllers.
Technical Context
The LT4294IMS#PBF implements IEEE 802.3bt single-signature PD detection using a precision 24.4 kΩ temperature-compensated signature resistor between VPORT and GND, with detection voltage range of 1.5–10 V and reset threshold of 2.6–5.6 V. Its classification logic supports RCLASS/RCLASS++ resistor programming for Classes 0–8 (13W–71.3W) and interprets PSE-allocated power via T2P open-drain output duty cycle (25%/50%/Hi-Z).
It integrates hot-swap control with VHSON = 35–37 V and VHSON–VHSOFF hysteresis of 3 V, enabling controlled inrush via external CGATE capacitor; supply current remains ≤0.9 mA during classification and ≤2 mA during mark events. Overtemperature protection activates above TJ = 150°C, pulling HSGATE low to disable power delivery.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VPORT Operating Input Voltage | 60 V max - defines maximum PoE port voltage before overvoltage shutdown |
| Detection Signature Resistance | 24.4 kΩ ±0.7 kΩ - precise, temperature-compensated value enabling reliable IEEE 802.3 detection |
| T2P Frequency | 690–990 Hz - determines PSE power negotiation timing resolution in 802.3bt mode |
| Classification Events Supported | Up to 5 events - enables full Class 8 (71.3W) allocation and demotion handling per IEEE 802.3bt |
| Junction Temperature Range | –40°C to 85°C - specifies operational limits for industrial/outdoor deployment |
| AUX Threshold Voltage | 6.1–6.5 V - sets auxiliary supply takeover point, enabling dual-source operation from ≥9 V |
| Hot Swap Turn-On/Off Hysteresis | 3 V - prevents oscillation during PoE startup/shutdown transitions |
Pinout & Package
LT4294IMS#PBF uses a 10-lead plastic MSOP package (3.0 mm × 3.0 mm footprint, 0.5 mm pitch), with exposed pad not present (unlike DFN variant); GND pins (1, 5) provide low-inductance return paths, and thermal resistance θJC = 45°C/W ensures stable operation under sustained 71.3W load conditions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1, 5) | Ground reference and thermal sink | Must be connected to PCB ground plane; provides primary return path for classification, T2P, and PWRGD signals |
| AUX (Pin 2) | Auxiliary supply sense input | Sinks 3.2–7 µA hysteresis current below 6.3 V threshold to enable seamless transition to auxiliary power ≥9 V |
| RCLASS (Pin 3) | Primary classification resistor terminal | Connects to GND via 1% resistor (e.g., 49.9 Ω for Class 8) to set nominal classification current per Table 2 |
| RCLASS++ (Pin 4) | Secondary classification resistor terminal | Enables 5-event classification; presence of resistor selects Classes 5–8 and triggers T2P 25% duty cycle for Class 7/8 |
| T2P (Pin 6) | PSE type/power indicator output | Open-drain output encoding allocated power: Hi-Z = ≤13W, Low-Z = 25.5W, 50% = ≤51W, 25% = ≤71.3W |
| PWRGD (Pin 7) | Power good status output | Open-drain signal held low until HSGATE reaches ~7 V above HSSRC, enabling safe downstream power-up |
| HSSRC (Pin 8) | External MOSFET source connection | Direct tie to source of N-channel hot-swap FET; establishes reference for gate drive and current sensing |
| HSGATE (Pin 9) | Hot-swap MOSFET gate driver | Provides IGPU = –27 to –18 µA pull-up and 200 µA pull-down to ramp external FET gate voltage linearly |
| VPORT (Pin 10) | PoE input rail and FET drain node | Accepts 802.3bt-compliant 0–60 V input; connects to drain of external N-MOSFET and internal signature/classification circuitry |
Key Features
| Feature | Design Value |
|---|---|
| IEEE 802.3bt single-signature compliance | Supports full Class 0–8 (13W–71.3W) allocation with 5-event classification and demotion handling per Table 1 |
| Integrated signature resistor | 24.4 kΩ ±0.7 kΩ trimmed and temperature-compensated - eliminates external component and improves detection margin |
| Configurable auxiliary power override | Operates with VAUX as low as 9 V via AUX pin threshold (6.3 V) and hysteresis - enables hybrid PoE + DC/AC backup |
| External N-channel hot-swap MOSFET control | Charge pump-based gate drive (VGOC = 10–18 V) reduces conduction loss vs. P-channel solutions - improves system efficiency >95% |
| Overtemperature protection | Active at TJ > 150°C - pulls HSGATE low to disable FET and prevent thermal runaway during abnormal classification or surge events |
| Pin compatibility with LT4275 family | Identical pinout to LT4275A/B/C - allows drop-in replacement in LTPoE++ designs without PCB revision |
Applications
| Outdoor Security Cameras | Commercial Information Displays |
|---|---|
Use Scenario: IP cameras deployed in unconditioned environments requiring PoE+ or PoE++ power and data over single Ethernet cable. IC Role / Device Role / Timing Role: LT4294IMS#PBF acts as the IEEE 802.3bt PD interface controller, managing detection, classification, and hot-swap sequencing while communicating allocated power via T2P duty cycle. Use Value: Enables 71.3W operation for pan-tilt-zoom (PTZ), heater, and IR illumination subsystems without external heatsinks, leveraging its 125°C junction-rated thermal protection. |
Use Scenario: Large-format digital signage in retail or transportation hubs needing robust, high-power PoE delivery with auxiliary fallback. IC Role / Device Role / Timing Role: LT4294IMS#PBF serves as the primary PD controller, coordinating with LT4321 ideal diode bridge to maintain >96% end-to-end efficiency and support dual-input (PoE + 24VAC) operation. Use Value: Auxiliary override down to 9V ensures continuous display operation during PoE outages; 5-event classification guarantees full 71.3W allocation from Type 4 PSEs. |
| High-Temperature Industrial Sensors | Wireless Data Access Points |
Use Scenario: Factory-floor sensors and edge gateways operating in ambient temperatures up to 85°C with strict thermal constraints. IC Role / Device Role / Timing Role: LT4294IMS#PBF functions as the PoE interface controller, using its –40°C to 85°C rated MSOP package and integrated thermal shutdown to sustain reliability without derating. Use Value: Eliminates need for discrete thermal monitoring ICs; overtemperature protection triggers only during sustained overload, preserving normal operation under transient loads. |
Use Scenario: High-density Wi-Fi 6/6E access points requiring >30W PoE power for multi-radio RF front-ends and baseband processing. IC Role / Device Role / Timing Role: LT4294IMS#PBF manages IEEE 802.3bt mutual identification and negotiates 51W–71.3W allocation via T2P signaling, synchronizing with downstream DC/DC converters. Use Value: 25% T2P duty cycle directly indicates Class 7/8 power availability, allowing firmware to enable full RF transmit chains without overloading the PSE. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar powered device interface controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT4294HMS#PBF | Same functionality and pinout, but rated for –40°C to 125°C junction temperature | Required for extended-temperature industrial or automotive under-hood deployments | Select when ambient operating temperature exceeds 85°C or when higher thermal headroom is needed for sustained 71.3W operation |
| LT4275CMS#PBF | LTPoE++ compliant (up to 90W), lacks IEEE 802.3bt 5-event classification and T2P encoding logic | Designed for legacy LTPoE++ PSE ecosystems; not interoperable with standard 802.3bt infrastructure | Choose only if deploying into existing LTPoE++ networks; not suitable as direct replacement for 802.3bt-only systems |
Compared with LT4294HMS#PBF, the LT4294IMS#PBF offers identical feature set and electrical performance but trades extended temperature capability for lower cost and qualification in standard industrial environments; versus LT4275CMS#PBF, it provides native 802.3bt compliance and PSE power reporting-critical for standards-conforming deployments.
Availability
LT4294IMS#PBF is available at Aetrix Electronics and suitable for outdoor security camera equipment, commercial information displays, and high-temperature industrial sensor systems requiring stable component supply across multi-year production cycles.
Supply support for LT4294IMS#PBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and power management.
The LT4294IMS#PBF belongs to Analog Devices' Power over Ethernet (PoE) PD controller product line, engineered specifically for IEEE 802.3bt-compliant high-power powered devices demanding robust classification, thermal resilience, and auxiliary supply flexibility.
FAQ
What is the maximum power level supported by the LT4294IMS#PBF?
The LT4294IMS#PBF supports up to 71.3W of input power as defined by IEEE 802.3bt Class 8. This is achieved through 5-event classification using RCLASS and RCLASS++ resistors configured per Table 2. The device communicates allocated power via T2P duty cycle (25% for Class 7/8), and its 60 V VPORT rating and thermal protection ensure safe operation at full load in the –40°C to 85°C ambient range.
How does the LT4294IMS#PBF handle auxiliary power override?
The LT4294IMS#PBF enters auxiliary power override mode when the AUX pin voltage exceeds 6.3 V (VAUXT), enabling operation from as low as 9 V input. In this mode, the signature resistor disconnects, classification is disabled, HSGATE pulls low, PWRGD goes high-impedance, and T2P outputs 25% duty cycle indicating maximum available power. The AUX pin's 3.2–7 µA hysteresis current ensures noise-immune switching between PoE and auxiliary sources.
Is the LT4294IMS#PBF pin-compatible with other Analog Devices PD controllers?
Yes, the LT4294IMS#PBF is pin-compatible with the LT4275A/B/C family of LTPoE++ PD controllers. This allows straightforward migration from LTPoE++ to IEEE 802.3bt systems without PCB layout changes. However, firmware must be updated to interpret T2P duty cycle (not present in LT4275) and support 5-event classification logic unique to the LT4294IMS#PBF.
What external components are required for basic LT4294IMS#PBF operation?
Minimum external components for LT4294IMS#PBF include: a 0.1 µF VPORT-to-GND capacitor (for IEEE impedance compliance), two 1% classification resistors (RCLS and RCLS++) tied from RCLASS/RCLASS++ to GND per Table 2, an external N-channel MOSFET (e.g., PSMN040-100MSE) driven by HSGATE/HSSRC, and a TVS diode (e.g., SMAJ58A) from VPORT to GND for surge protection. An optional CGATE capacitor sets inrush current.
Does the LT4294IMS#PBF support dual-signature PD topologies?
No-the LT4294IMS#PBF is designed explicitly for IEEE 802.3bt single-signature PD topologies. All documentation, classification tables, and T2P behavior assume single-signature operation. While it may be deployed in dual-signature systems with additional external circuitry, such use is outside the scope of official specification and requires consultation with Analog Devices Applications Engineering for validation.
LT4294IMS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Controller (PD)
- Number of Channels:
- 1
- Power - Max:
- 71 W
- Internal Switch(s):
- No
- Auxiliary Sense:
- Yes
- Standards:
- 802.3at (PoE+), 802.3af (PoE), 802.3bt
- Voltage - Supply:
- 60V (Max)
- Current - Supply:
- 2mA
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP
LT4294IMS#PBF FAQ
1.How can I place an order for LT4294IMS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT4294IMS#PBF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LT4294IMS#PBF reliable?
The price and inventory of LT4294IMS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT4294IMS#PBF is usually 5 days.
3.What payment methods are accepted for LT4294IMS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT4294IMS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT4294IMS#PBF?
LT4294IMS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT4294IMS#PBF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LT4294IMS#PBF?
For technical support, including LT4294IMS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT4294IMS#PBF requirements.
6.How does Aetrix verify that LT4294IMS#PBF is sourced from the original manufacturer or authorized distributors?
All LT4294IMS#PBF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LT4294IMS#PBF meets industry standards.
7.What is the process for return or replacement of LT4294IMS#PBF?
All LT4294IMS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT4294IMS#PBF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LT4294IMS#PBF part is unused and in its original packaging.
Return procedure for LT4294IMS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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