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Analog Devices Inc. LT4275BIDD#PBF
- Part No.:
- LT4275BIDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT4275BIDD#PBF.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:5,647
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Product details
Overview
LT4275BIDD#PBF from Analog Devices (formerly Linear Technology) is an IEEE 802.3at Type 2 Powered Device (PD) controller for PoE+ applications, delivering up to 25.5W at the RJ45 connector, featuring integrated signature resistor, programmable inrush control via external capacitor, and open-drain T2P/PWRGD outputs for PSE type indication and power-good signaling - used in outdoor security cameras and commercial displays requiring robust Ethernet-powered operation.
For engineers reviewing the LT4275BIDD#PBF datasheet, LT4275BIDD#PBF pinout, LT4275BIDD#PBF application, or LT4275BIDD#PBF equivalent, key selection considerations include its 25.5W IEEE 802.3at compliance, 10-lead DFN (3mm × 3mm) package with exposed GND pad, –40°C to 85°C operating range, 100V absolute maximum input voltage, and support for auxiliary supply override via AUX pin.
Technical Context
The LT4275BIDD#PBF implements IEEE 802.3at 2-event physical layer classification using RCLASS pin to set 40mA class 4 current draw, and drives T2P as an open-drain output pulled low to indicate Type 2 PSE detection. It uses an internal charge pump to drive an external N-channel MOSFET gate (HSGATE), eliminating need for P-channel devices.
Its hot-swap control features adjustable inrush via CGATE capacitor, undervoltage lockout thresholds of 27V (turn-on) and 21.5V (turn-off) when IEEEUVLO is grounded, and thermal protection that pulls down HSGATE and floats PWRGD above 150°C junction temperature. Signature resistance is precisely trimmed to 24.4kΩ ±0.7kΩ across –40°C to 125°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Delivered Power | 25.5W - IEEE 802.3at Type 2 compliant power level at PD port |
| Input Voltage Range | 23V to 60V - Valid operating VPORT range for powered-on mode |
| Signature Resistance | 24.4kΩ ±0.7kΩ - Precision, temperature-compensated value enabling reliable 25kΩ detection by PSE |
| Classification Current | 40mA - Class 4 load current set by 34.8Ω RCLASS resistor per IEEE 802.3at |
| Absolute Max VPORT | 100V - Withstands transient overvoltage events without damage |
| Operating Temp Range | –40°C to 85°C - Specified junction temperature range for industrial deployment |
| HSGATE Drive Capability | 18–27µA pull-up, 200µA pull-down - Sufficient to charge external N-MOSFET gate capacitance for controlled inrush |
Pinout & Package
LT4275BIDD#PBF is housed in a 10-lead (3mm × 3mm) plastic DFN package with exposed GND pad (Pin 11), requiring soldering to PCB ground plane for thermal and electrical integrity. Pin 1 is marked by notch; top-side marking is "LGBV".
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IEEEUVLO (1) | Hot-swap UVLO threshold select | Grounding enables IEEE-compliant 27V/21.5V turn-on/turn-off; floating lowers thresholds |
| AUX (2) | Auxiliary supply enable input | Sinking ≥4µA below 6.3V triggers auxiliary override mode, disconnecting signature and disabling classification |
| RCLASS (3) | Classification resistor connection | 34.8Ω to GND sets 40mA class 4 current for IEEE 802.3at Type 2 recognition |
| RCLASS++ (4) | Not connected (NC) | Unbonded in LT4275B; reserved for LTPoE++ variants only |
| GND (5) | Power and signal reference | Primary ground return; exposed pad (Pin 11) must be soldered to PCB GND |
| T2P (6) | PSE type indicator output | Open-drain; pulled low to signal Type 2 (25.5W) PSE detection after PWRGD assertion |
| PWRGD (7) | Power-good status output | Open-drain; remains low until HSGATE reaches ~7V above HSSRC, enabling isolated supply sequencing |
| HSSRC (8) | External MOSFET source connection | Connects to source of N-channel hot-swap FET; forms source-follower configuration with HSGATE |
| HSGATE (9) | External MOSFET gate driver | Charge-pump-driven output controlling gate voltage ramp rate and inrush current magnitude |
| VPORT (10) | PD input power rail | Accepts PoE power from Ethernet magnetics; connects to drain of external N-MOSFET |
Key Features
| Feature | Design Value |
|---|---|
| N-channel MOSFET interface | Eliminates costly P-channel FET; supports low RDS(ON) devices for >90% system efficiency |
| Programmable inrush current | Set via external CGATE capacitor; enables precise IINRUSH ≈ 100mA per IEEE 802.3at requirement |
| Integrated signature resistor | 24.4kΩ ±0.7kΩ trimmed on-die; eliminates external precision resistor and layout sensitivity |
| Auxiliary supply override | Enables seamless switchover to 9–60V DC or 24V AC auxiliary input without disrupting upstream PSE negotiation |
| Thermal protection | Automatic HSGATE shutdown and PWRGD float above 150°C junction temperature; self-recovering on cooldown |
Applications
| Outdoor Security Cameras | Commercial Digital Signage |
|---|---|
Use Scenario: IP-based PTZ cameras deployed in unconditioned environments with single-cable power + data delivery over Cat5e/6. IC Role / Device Role / Timing Role: PD controller managing IEEE 802.3at classification, inrush limiting, and power-good handoff to isolated DC/DC converter. Use Value: Enables 25.5W delivery for pan/tilt/zoom motors, heater elements, and high-brightness LCD backlights without local AC wiring. |
Use Scenario: Large-format indoor/outdoor displays in retail, transit hubs, and corporate lobbies requiring remote power and firmware updates. IC Role / Device Role / Timing Role: Hot-swap controller ensuring safe power-up sequence and continuous PSE communication via T2P status reporting. Use Value: Supports sustained 25.5W load for LED backlight drivers and video processing SoCs while maintaining IEEE interoperability. |
| Industrial IoT Gateways | High-Temperature Network Switches |
Use Scenario: Edge gateways aggregating sensor data in factory automation systems where conduit space limits separate power runs. IC Role / Device Role / Timing Role: Robust PD interface with –40°C to 85°C operation, thermal shutdown, and auxiliary supply fallback for brownout resilience. Use Value: Ensures uninterrupted operation during ambient temperature excursions and allows graceful failover to local 24V DC backup. |
Use Scenario: Managed switches mounted inside hot enclosures or near HVAC equipment requiring extended thermal margin. IC Role / Device Role / Timing Role: IEEE-compliant PD controller with 100V abs max rating and exposed-pad thermal path for conduction cooling. Use Value: Maintains reliable classification and power delivery even at 85°C ambient, reducing need for forced-air cooling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PoE+ PD controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC4265 | Integrates 100V/1A internal hot-swap switch; no external MOSFET required | Better suited for space-constrained designs; lower BOM count but higher thermal dissipation in switch | Select LTC4265 when board area is critical and peak load ≤1A; LT4275BIDD#PBF preferred for higher efficiency and thermal isolation via external FET |
| MAX5984A | Supports IEEE 802.3at only; lacks AUX override and T2P PSE-type reporting | No auxiliary supply handoff capability; limited to pure PoE+ deployments without backup power | Choose MAX5984A for cost-sensitive, fixed 25.5W applications without auxiliary requirements; LT4275BIDD#PBF adds design flexibility for hybrid power architectures |
Compared with LTC4265 and MAX5984A, the LT4275BIDD#PBF provides superior thermal management via external N-MOSFET, full auxiliary supply override with hysteresis, and real-time PSE type feedback through T2P - making it optimal for industrial and outdoor PoE+ systems demanding reliability and power architecture flexibility.
Availability
LT4275BIDD#PBF is available at Aetrix Electronics and suitable for outdoor security camera systems, commercial digital signage installations, and industrial IoT gateways requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LT4275BIDD#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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for the LT4275 family.
The LT4275BIDD#PBF belongs to Linear's PoE PD controller product line, designed specifically for IEEE 802.3at-compliant powered devices requiring high-efficiency N-MOSFET interface, robust thermal protection, and auxiliary supply integration.
FAQ
What is the maximum power delivered by the LT4275BIDD#PBF?
The LT4275BIDD#PBF delivers up to 25.5W of power at the PD RJ45 connector, fully compliant with IEEE 802.3at Type 2 specifications. This rating assumes proper external N-channel MOSFET selection, adequate heatsinking, and adherence to inrush current limits defined in the standard. The LT4275BIDD#PBF does not support LTPoE++ or higher power levels beyond 25.5W.
Does the LT4275BIDD#PBF require an external MOSFET?
Yes, the LT4275BIDD#PBF requires an external N-channel MOSFET connected between VPORT (drain), HSSRC (source), and HSGATE (gate). Its internal charge pump drives the gate to control inrush and steady-state conduction. This architecture enables higher efficiency and better thermal performance than integrated-switch alternatives. The LT4275BIDD#PBF itself contains no power switch.
How does the T2P pin function on the LT4275BIDD#PBF?
The T2P pin on the LT4275BIDD#PBF is an open-drain output that pulls low after PWRGD becomes valid to indicate detection of an IEEE 802.3at Type 2 PSE. It remains low continuously - unlike the LT4275A's pulsed T2P behavior for LTPoE++. T2P is unconnected (NC) on LT4275C and functions only on LT4275A/B variants.
Can the LT4275BIDD#PBF operate with auxiliary power input?
Yes, the LT4275BIDD#PBF supports auxiliary power override via the AUX pin. When AUX voltage exceeds 6.3V (VAUXT), the device disconnects the signature resistor, disables classification, pulls down HSGATE, and floats PWRGD - allowing seamless transition to 9–60V DC or 24V AC auxiliary supply. Hysteresis is provided by sinking 4–8µA below VAUXT.
What package type is used for the LT4275BIDD#PBF?
The LT4275BIDD#PBF uses a 10-lead (3mm × 3mm) plastic DFN package with exposed GND pad (Pin 11). This package offers low thermal resistance (θJC = 5°C/W) and requires soldering the exposed pad directly to PCB ground for optimal thermal performance and electrical stability. The top-side marking is "LGBV".
LT4275BIDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Controller (PD)
- Number of Channels:
- 1
- Power - Max:
- 25.5 W
- Internal Switch(s):
- No
- Auxiliary Sense:
- Yes
- Standards:
- 802.3at (PoE+), 802.3af (PoE)
- Voltage - Supply:
- 23V ~ 60V
- Current - Supply:
- 2mA (Max)
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT4275BIDD#PBF FAQ
1.How can I place an order for LT4275BIDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT4275BIDD#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 LT4275BIDD#PBF reliable?
The price and inventory of LT4275BIDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT4275BIDD#PBF is usually 5 days.
3.What payment methods are accepted for LT4275BIDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT4275BIDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT4275BIDD#PBF?
LT4275BIDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT4275BIDD#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 LT4275BIDD#PBF?
For technical support, including LT4275BIDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT4275BIDD#PBF requirements.
6.How does Aetrix verify that LT4275BIDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT4275BIDD#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 LT4275BIDD#PBF meets industry standards.
7.What is the process for return or replacement of LT4275BIDD#PBF?
All LT4275BIDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT4275BIDD#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 LT4275BIDD#PBF part is unused and in its original packaging.
Return procedure for LT4275BIDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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