Analog Devices Inc. LTC4263CS#PBF

Overview

LTC4263CS#PBF from Analog Devices (formerly Linear Technology) is a single-channel IEEE 802.3af-compliant Power Sourcing Equipment (PSE) controller with integrated power MOSFET, autonomous PD detection/classification, and AC/DC disconnect sensing. It operates from a single –48V supply, delivers up to 15.4W per port, supports class-dependent current limiting (ICUT = 95–395 mA), and implements robust fault protection including foldback, thermal shutdown, and high-speed short-circuit limiting (IFAULT = 500–800 mA). It is used in standalone or multi-port Ethernet power injectors for IP phones and wireless access points.

For engineers reviewing the LTC4263CS#PBF datasheet, LTC4263CS#PBF pinout, LTC4263CS#PBF application, or LTC4263CS#PBF equivalent, key selection criteria include IEEE 802.3af compliance level, internal MOSFET R_ON (1.5–3.0 Ω), programmable power management across multiple ports, midspan/endpoint mode configuration, and LED-driven port status indication with fault-code blinking.

Technical Context

The LTC4263CS#PBF implements fully autonomous PSE operation using force-current two-point signature detection (IDET = 160–275 μA) and voltage-based classification (VCLASS = 16.5–20.5 V), eliminating need for host microcontroller. Its control architecture integrates inrush management via internal sense resistor, configurable detection backoff timing (tDBO = 3.0–3.4 s), and dual-mode disconnect sensing-AC disconnect enabled via OSC/ACOUT pins with 0.15 μF capacitance threshold, or DC disconnect via OUT pin monitoring.

Power allocation uses analog current-source-based PWRMGT signaling (–17.9 to –75.6 μA per class), where shared RC network sets system-wide power budget. Fault response includes hierarchical current limiting: high-speed IFAULT activation (500–800 mA), followed by ILIM clamping (405–445 mA), then foldback (IFB = 30–180 mA) and thermal protection, all coordinated without external intervention.

Key Specifications

Pinout & Package

Package: 14-lead plastic SO (Small Outline), 0°C to 70°C operating range. Pin 15 (exposed pad) is absent - only DFN variants include exposed VSS pad.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PSE controller applications.

Compared with TPS23753APWR, LTC4263CS#PBF reduces BOM count and layout area by integrating the power MOSFET and thermal protection, while compared with LTC4270CDE#PBF, it offers lower system cost and simpler analog power management for basic 802.3af deployments.

Availability

LTC4263CS#PBF is available at Aetrix Electronics and suitable for IP telephony injectors, wireless access point midspans, industrial IoT gateways, and smart building sensor hubs requiring stable component supply and long-term industrial availability.

Supply support for LTC4263CS#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LTC4263CS#PBF belongs to Linear's Power over Ethernet (PoE) PSE controller product line, designed specifically for simplified, autonomous, single-port IEEE 802.3af power injection in cost-sensitive and space-constrained networking equipment.

FAQ

What is the operating temperature range for the LTC4263CS#PBF?

The LTC4263CS#PBF is specified for commercial temperature operation from 0°C to 70°C. This distinguishes it from the 'I' grade (LTC4263IS#PBF), which supports –40°C to 85°C. The 'C' suffix in LTC4263CS#PBF explicitly denotes the commercial grade, validated across this range for stability in office and light-industrial environments.

Does the LTC4263CS#PBF include an integrated power MOSFET?

Yes, the LTC4263CS#PBF integrates a power MOSFET with guaranteed on-resistance of 1.5–3.0 Ω (at 350 mA). This eliminates the need for external switching components, simplifies layout, and enables direct connection of the OUT pins to Ethernet magnetics. Thermal protection is built-in to safeguard the MOSFET during sustained overload or short-circuit events.

How does the LTC4263CS#PBF handle IEEE 802.3af classification and current limiting?

The LTC4263CS#PBF performs automatic classification by applying ~18 V and measuring current draw (ICLASS = 55–75 mA), identifying Classes 0–4. When ENFCLS is high, it enforces class-specific ICUT thresholds: 95 mA (Class 1), 175 mA (Class 2), and 375 mA (Class 0/3/4). If ENFCLS is low, ICUT remains fixed at 375 mA regardless of detected class.

Can the LTC4263CS#PBF support both endpoint and midspan PSE configurations?

Yes, the LTC4263CS#PBF supports both modes via the MIDSPAN pin. When MIDSPAN is pulled high, it enables 3.2-second detection backoff for midspan operation to prevent conflicts with endpoint PSEs on the same link. When MIDSPAN is low, it operates as an endpoint PSE with no backoff delay - allowing immediate re-detection after failure.

What is the purpose of the PWRMGT pin on the LTC4263CS#PBF?

The PWRMGT pin on the LTC4263CS#PBF sources a class-proportional current (–17.9 to –75.6 μA) to implement analog power budgeting across multiple ports. By tying PWRMGT pins together with a shared RC network to VSS, designers allocate total 48 V supply capacity without digital communication - the LTC4263CS#PBF checks PWRMGT voltage (<1 V) before enabling each port.