Texas Instruments TPS2375PW

Overview

TPS2375PW from Texas Instruments is an IEEE 802.3af-compliant powered device (PD) controller IC for Power over Ethernet applications, integrating a 0.58-Ω 100-V low-side MOSFET switch, fixed 450-mA operational current limit, and open-drain power-good (PG) output. It operates across –40°C to 85°C, supports Class 3 PD detection/classification, and enables PoE-powered VoIP phones, WLAN access points, and security cameras.

For engineers reviewing the TPS2375PW datasheet, TPS2375PW pinout, TPS2375PW application, or TPS2375PW equivalent, key selection criteria include its 39.3-V UVLO rising threshold, 30.5-V falling threshold, 100-V absolute maximum RTN voltage rating, programmable inrush current via ILIM pin, and compatibility with silicon rectifier-based front-end designs per IEEE 802.3af.

Technical Context

The TPS2375PW implements full IEEE 802.3af PD state sequencing-detection (1.4–10.1 V), classification (13–21 V), and powered operation-with internal comparators featuring hysteresis for stable mode transitions. Its DET pin sinks current through an external 24.9-kΩ resistor to generate the 25-kΩ incremental resistance signature required for PSE detection.

Classification is performed by sourcing current through an external CLASS resistor (e.g., 357 Ω for Class 3), while the ILIM pin sets inrush current limit via a 178-kΩ resistor (100–180 mA range). The integrated 0.58-Ω MOSFET switches the RTN return path, and PG asserts high-impedance when RTN voltage exceeds 10.0 V and inrush has terminated.

Key Specifications

Pinout & Package

TSSOP-8 package (PW suffix), 3.0 mm × 4.4 mm, 0.65-mm pitch, exposed thermal pad (not electrically connected).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS2376PW and TPS2377PW, the TPS2375PW offers the highest UVLO hysteresis (8.8 V) and is optimized for full IEEE 802.3af compliance-making it the preferred choice for new designs targeting interoperability with modern PSE infrastructure.

Availability

TPS2375PW is available at Aetrix Electronics and suitable for VoIP phones, WLAN access points, security cameras, and POS terminals requiring stable component supply with full IEEE 802.3af certification support.

Supply support for TPS2375PW 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

Texas Instruments is a global semiconductor company specializing in analog and embedded processing technologies, with leadership in power management and interface solutions.

The TPS2375PW belongs to TI's Power over Ethernet (PoE) Powered Device Controller product line, designed specifically to simplify IEEE 802.3af-compliant PD implementation in networked endpoint devices.

FAQ

What is the primary function of the TPS2375PW in a PoE system?

The TPS2375PW serves as a fully integrated IEEE 802.3af powered device (PD) controller that manages detection, classification, undervoltage lockout, inrush current limiting, and power-good signaling. It controls the low-side power switch to deliver regulated power to downstream circuitry while ensuring strict compliance with PoE standards. The TPS2375PW eliminates the need for discrete components in the PD front-end, reducing design complexity and board space.

How does the TPS2375PW implement IEEE 802.3af detection and classification?

The TPS2375PW implements detection by sinking current through the DET pin into an external 24.9-kΩ resistor to generate the required 25-kΩ incremental resistance signature. During classification, it sources current from the CLASS pin through an external resistor (e.g., 357 Ω for Class 3) within the 13–21 V input window. The TPS2375PW uses internal comparators with hysteresis to transition cleanly between states. These functions are fully implemented in hardware and require no firmware.

What is the purpose of the ILIM pin on the TPS2375PW, and how is it configured?

The ILIM pin on the TPS2375PW sets the inrush current limit during power-up by connecting an external resistor to VSS. Using R_ILIM = 178 kΩ yields a typical inrush current of 130 mA, preventing input voltage sag during bulk capacitor charging. The supported resistor range is 62.5 kΩ to 500 kΩ, corresponding to 100–180 mA inrush. The ILIM pin must never be left floating or shorted to VSS, as either condition disables inrush control and risks PSE shutdown.

Does the TPS2375PW require an external MOSFET, or is the pass device integrated?

The TPS2375PW integrates a 0.58-Ω, 100-V rated low-side MOSFET pass device, eliminating the need for an external transistor. This internal switch handles the full PD return current path (up to 515 mA absolute maximum) and is controlled directly by the controller's internal logic. The integration reduces bill-of-materials cost, simplifies layout, and improves thermal performance compared to discrete solutions.

What are the key differences between TPS2375PW, TPS2376PW, and TPS2377PW?

The TPS2375PW features fixed IEEE 802.3af-optimized UVLO thresholds (39.3 V rise / 30.5 V fall), while the TPS2376PW adds a dedicated UVLO pin for resistor-divider programmability, and the TPS2377PW uses legacy UVLO thresholds (35.1 V rise / 30.5 V fall) for backward compatibility. All three share identical pinouts (except UVLO/NC), inrush control, classification, and pass device specs. The TPS2375PW is recommended for new designs targeting full 802.3af compliance.