My Inquiry
My Account
Analog Devices Inc. LTC4279IUFD#TRPBF
- Part No.:
- LTC4279IUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LTC4279IUFD#TRPBF.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:5,496
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC4279IUFD#TRPBF from Analog Devices is a single-port, fully autonomous Power Sourcing Equipment (PSE) controller for IEEE 802.3at Type 1/Type 2 and LTPoE++ PoE systems. It delivers up to 90W compliant power without a microcontroller, uses a 0.1Ω sense resistor and external MOSFET for ultra-low heat dissipation, and supports dual-signature PD detection and UltraPWR mode for custom devices drawing up to 123W. It is deployed in PoE midspan injectors and endpoint switches powering security cameras and femtocells.
For engineers reviewing the LTC4279IUFD#TRPBF datasheet, LTC4279IUFD#TRPBF pinout, LTC4279IUFD#TRPBF application, or LTC4279IUFD#TRPBF equivalent, key selection criteria include autonomous IEEE/LTPoE++ compliance, 20-pin QFN package thermal performance (θJA = 43°C/W), classification-dependent current thresholds (e.g., VLIM = 240 mV for LTPoE++ 90W), and pin-selectable LEGACY/MID/DUALPD modes for legacy PD support and midspan timing.
Technical Context
The LTC4279IUFD#TRPBF implements a dual-mode 4-point PD detection architecture-combining forced voltage (7–9 V) and forced current (143–180 µA) stages-with ±80V surge protection on the OUT pin and Kelvin-sense current monitoring via SENSE/VSSK. Its gate driver delivers 30 mA fast pull-down and 12 V (typ) gate drive above VEE to control external MOSFETs.
Classification is performed across five IEEE classes and four LTPoE++ levels (38.7W–90W), with ICUT and ILIM thresholds dynamically scaled per PWRMODE resistor setting (e.g., RPM = 10.0 kΩ for 90W). DC disconnect sensing uses VMIN = 0.75 mV threshold, and maintain-power signature (MPS) timing complies with tDIS = 350 ms and tMPS = 3.6 ms.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Compliance | IEEE 802.3at Type 1 (13W), Type 2 (25.5W), and LTPoE++ (38.7W/52.7W/70W/90W); UltraPWR mode supports up to 123W |
| Detection Method | Proprietary 4-point detection: forced voltage (7–9 V) + forced current (143–180 µA); rejects RPD < 15.5 kΩ or > 32 kΩ |
| Current Sensing | 0.1 Ω external sense resistor; VCUT = 232 mV (LTPoE++ 90W), VLIM = 240 mV (LTPoE++ 90W), VMIN = 0.75 mV (DC disconnect) |
| Package & Thermal | 20-pin (4 mm × 5 mm) QFN; θJA = 43°C/W, θJC = 3.4°C/W; exposed pad = VEE |
| Operating Range | –40°C to +85°C ambient; VEE supply = –45 V to –65 V (depending on mode); absolute max OUT = ±80 V relative to VEE |
| Timing Accuracy | tDET = 410 ms (detection), tPON = 82 ms (power-on delay), tDIS = 350 ms (MPS dropout), tMPS = 3.6 ms (MPS pulse width) |
| Configuration Pins | MID (midspan timing enable), LEGACY (pre-IEEE PD support), DUALPD (dual-signature PD detection), PWRMODE (RPM resistor sets max power level) |
Pinout & Package
Package: 20-lead (4 mm × 5 mm) plastic QFN with exposed thermal pad connected to VEE. Pin 21 (exposed pad) is electrically VEE and must be soldered for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VEE | Main negative PoE supply input | Accepts –45 V to –65 V (mode-dependent); absolute max rating: –0.3 V to –80 V relative to AGND |
| OUT | Port output voltage monitor | Connected to Ethernet port; includes internal 500 kΩ pull-up to AGND when idle; ±80 V surge protected |
| SENSE | Current sense input | Monitors voltage across 0.1 Ω sense resistor between SENSE and VSSK; triggers VCUT/VLIM faults |
| VSSK | Kelvin sense return for VEE | Must connect to sense resistor low-side node-not to VEE plane-to eliminate PCB trace resistance error |
| GATE | External MOSFET gate driver | Drives gate 12 V above VEE (typ); 30 mA fast pull-down; reduces voltage during current limiting to maintain ILIM |
| AGND | Analog ground reference | Return for VEE supply via 10 Ω resistor; separate from digital/power ground to minimize noise coupling |
| PWRMODE | Max power mode selection | Resistor to VEE sets power level: 2.37 kΩ = 13W, 10.0 kΩ = 90W, 13.0 kΩ = UltraPWR (up to 123W) |
| LEGACY | Legacy PD detection enable | High = enables pre-IEEE PD detection and 13W allocation for Class 0–3; internally pulled down to VEE |
| MID | Midspan operation mode | High = enables 2.5 s backoff timer and physical-layer classification; internally pulled down to VEE |
| DUALPD | Dual-signature PD detection enable | High = allows RSIG-too-Low detection results to proceed to classification; requires PWRMODE ≥ 52.7W |
| RESET | Active-low reset input | Logic low holds device inactive; internal pull-up to VROC (3.6 V); ignores glitches < 4.5 µs |
| LED | Open-drain port status indicator | Pulls down to VEE when port is powered; supports 10 mA sink; used for system status indication |
| DNC | Do Not Connect | Pins 2, 3, 4, 11, 12, 13, 14, 15, 16, 17, 18, 19 are unconnected; must remain floating |
Key Features
| Feature | Design Value |
|---|---|
| Autonomous IEEE/LTPoE++ Compliance | Full detection, classification, and power application without MCU; meets all 802.3at timing and electrical requirements |
| Ultra-Low Power Dissipation | 0.1 Ω sense resistor + low-RDS(ON) external MOSFET eliminates need for heatsinks; θJA = 43°C/W enables compact designs |
| Dual-Signature PD Support | Enables parallel detection of two Type 2 PD signatures; doubles inrush/cutoff/limit currents while maintaining IEEE compatibility |
| Robust Cable Surge Protection | ±80 V tolerance on OUT pin protects against induced transients on Ethernet cabling in industrial environments |
| Pin-Selectable Operating Modes | LEGACY, MID, DUALPD, and PWRMODE pins configure behavior at reset exit-no firmware required |
| High-Reliability 4-Point Detection | Forced voltage + forced current detection ensures immunity to false triggers from capacitive loads or legacy ports (e.g., 150 Ω terminations) |
Applications
| Security Camera Power Delivery | Femtocell Base Station Power |
|---|---|
|
Use Scenario: Outdoor IP security camera requiring 60W PoE+ power with surge immunity in unshielded CAT5e runs. IC Role / Device Role / Timing Role: LTC4279IUFD#TRPBF acts as endpoint PSE, performing autonomous detection/classification and delivering regulated 57V @ ~1.05A with tDIS = 350 ms MPS hold-off. Use Value: ±80V OUT pin protection prevents field failures from lightning-induced surges; 43°C/W thermal design sustains full load in enclosed enclosures. |
Use Scenario: Indoor small-cell base station needing 90W LTPoE++ power with dual-pair delivery over existing LAN infrastructure. IC Role / Device Role / Timing Role: LTC4279IUFD#TRPBF operates in LTPoE++ 90W mode (RPM = 10.0 kΩ), enabling 4-pair power delivery with VLIM = 240 mV current limiting. Use Value: Eliminates need for local AC adapters; autonomous operation reduces BOM count by removing MCU and associated firmware development. |
| PoE Midspan Injector | Legacy VoIP Phone Power Upgrade |
|
Use Scenario: Retrofit midspan injector adding PoE capability to non-PoE enterprise switches, supporting mixed Type 1/2/LTPoE++ PDs. IC Role / Device Role / Timing Role: LTC4279IUFD#TRPBF configured with MID = high enables 2.5 s backoff timer and physical-layer classification per IEEE midspan requirements. Use Value: Single-chip solution replaces multi-IC legacy designs; pin-selectable modes allow one PCB to support endpoint/midspan configurations. |
Use Scenario: Upgrading legacy analog phone infrastructure to support IEEE-compliant VoIP phones while retaining pre-802.3af devices. IC Role / Device Role / Timing Role: LTC4279IUFD#TRPBF with LEGACY = high detects and allocates 13W to pre-standard phones, while classifying IEEE PDs normally. Use Value: Avoids costly replacement of installed base; maintains interoperability across generations without manual configuration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PSE controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX5984AEUI+ | 16-pin SO package; supports only IEEE 802.3af/at (no LTPoE++); lower max power (30W); no UltraPWR or DUALPD modes | Suitable for cost-sensitive Type 1/2-only deployments where 90W or proprietary extensions are unnecessary | Select MAX5984AEUI+ when LTPoE++/UltraPWR features are not required and SO-16 footprint is preferred. |
| TPS23754PW | 20-pin TSSOP; supports 802.3af/at only; integrated 100V MOSFET (higher conduction loss); no Kelvin sense; θJA = 65°C/W | Better suited for low-volume, space-constrained designs where external MOSFET layout complexity must be avoided | Select TPS23754PW when board area is critical and thermal budget allows higher junction temperature rise. |
Compared with MAX5984AEUI+ and TPS23754PW, the LTC4279IUFD#TRPBF provides unique LTPoE++ 90W support, Kelvin-sense accuracy, and lowest thermal resistance (43°C/W), making it optimal for high-power, high-reliability midspan and endpoint PSEs demanding future-proof scalability.
Availability
LTC4279IUFD#TRPBF is available at Aetrix Electronics and suitable for PoE midspan injectors, enterprise switch endpoints, and industrial security systems requiring stable component supply, long lifecycle support, and guaranteed LTPoE++ compliance.
Supply support for LTC4279IUFD#TRPBF 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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC4279IUFD#TRPBF belongs to Analog Devices' Power over Ethernet (PoE) PSE controller product line, designed specifically for autonomous, high-efficiency, multi-standard power sourcing in enterprise and industrial infrastructure equipment.
FAQ
What is the maximum power delivery capability of the LTC4279IUFD#TRPBF?
The LTC4279IUFD#TRPBF supports up to 90W under LTPoE++ compliance (with RPM = 10.0 kΩ) and up to 123W in UltraPWR mode (RPM = 13.0 kΩ), contingent on VPSE supply voltage and external MOSFET capability. It does not deliver 123W under IEEE standards-UltraPWR is a proprietary high-current mode for custom PDs.
Does the LTC4279IUFD#TRPBF require a microcontroller to operate?
No, the LTC4279IUFD#TRPBF is fully autonomous: it performs IEEE 802.3at and LTPoE++ detection, classification, and power application without any firmware or host processor. All configuration is done via hardware pins (MID, LEGACY, DUALPD, PWRMODE) sampled at reset exit.
How does the LTC4279IUFD#TRPBF protect against false PD detection from legacy network ports?
The LTC4279IUFD#TRPBF uses a proprietary 4-point detection method-two forced-voltage and two forced-current measurements-that rejects common-mode resistances below 15.5 kΩ (e.g., 150 Ω Ethernet port terminations) and above 32 kΩ, preventing accidental power application to non-PD equipment.
What is the purpose of the VSSK pin on the LTC4279IUFD#TRPBF?
The VSSK pin on the LTC4279IUFD#TRPBF provides a Kelvin sense connection to the low side of the 0.1 Ω current sense resistor. It must be routed separately from the main VEE power plane to eliminate PCB trace resistance error, ensuring accurate current limit (VLIM) and overcurrent (VCUT) thresholds.
Can the LTC4279IUFD#TRPBF support both endpoint and midspan PSE topologies?
Yes-the LTC4279IUFD#TRPBF supports both topologies via the MID pin: when MID = high, it enables midspan-specific timing (2.5 s backoff) and physical-layer classification; when MID = low, it operates as an endpoint PSE with standard IEEE timing. Both modes use the same LTC4279IUFD#TRPBF silicon.
LTC4279IUFD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Controller (PSE)
- Number of Channels:
- 1
- Power - Max:
- 90 W
- Internal Switch(s):
- No
- Auxiliary Sense:
- No
- Standards:
- 802.3at (PoE+), 802.3af (PoE), LTPoE++
- Voltage - Supply:
- 45V ~ 57V
- Current - Supply:
- 1.7mA
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (4x5)
LTC4279IUFD#TRPBF FAQ
1.How can I place an order for LTC4279IUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4279IUFD#TRPBF 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 LTC4279IUFD#TRPBF reliable?
The price and inventory of LTC4279IUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4279IUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC4279IUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4279IUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4279IUFD#TRPBF?
LTC4279IUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4279IUFD#TRPBF 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 LTC4279IUFD#TRPBF?
For technical support, including LTC4279IUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4279IUFD#TRPBF requirements.
6.How does Aetrix verify that LTC4279IUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC4279IUFD#TRPBF 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 LTC4279IUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC4279IUFD#TRPBF?
All LTC4279IUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4279IUFD#TRPBF, 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 LTC4279IUFD#TRPBF part is unused and in its original packaging.
Return procedure for LTC4279IUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC4279IUFD#TRPBF Tags
-
TPS2378DDAR
Texas Instruments
-
TPS23753APWR
Texas Instruments
-
TPS23756PWPR
Texas Instruments
-
TPS23750PWPR
Texas Instruments
-
MP8007GV-Z
Monolithic Power Systems Inc.
-
TPS23861PWR
Texas Instruments
-
TPS23753PWR
Texas Instruments
-
PD69201ILD-TR
Microchip Technology
-
SI3402-B-GM
Skyworks Solutions Inc.
-
SI3402-B-GMR
Skyworks Solutions Inc.
-
SI34071-A01-GMR
Skyworks Solutions Inc.
-
SI3404-A-GMR
Skyworks Solutions Inc.
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
