Texas Instruments TPS2375DRG4

Overview

TPS2375DRG4 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, 30.5 V/39.3 V UVLO thresholds, and open-drain power-good (PG) reporting. It enables PoE-powered VoIP phones, WLAN access points, and security cameras by managing detection, classification, inrush control, and thermal protection.

For engineers reviewing the TPS2375DRG4 datasheet, TPS2375DRG4 pinout, TPS2375DRG4 application, or TPS2375DRG4 equivalent, this page delivers verified electrical parameters, SOIC-8 package mapping, IEEE 802.3af state transition behavior, thermal shutdown at 135°C, and real-world design constraints including R(DET) = 24.9 kΩ and R(CLASS) = 255 Ω for Class 4 operation.

Technical Context

The TPS2375DRG4 implements a deterministic three-stage PoE state machine-detection (1.4–10.1 V), classification (13–21 V), and powered operation-with hysteresis-controlled comparators for stable mode transitions. Its internal 0.58-Ω MOSFET handles up to 515 mA RTN sinking current while supporting 100-V absolute maximum input voltage on VDD, RTN, DET, and PG pins.

It uses external resistors to configure critical functions: R(DET) = 24.9 kΩ sets detection signature impedance, R(CLASS) selects IEEE 802.3af Class 0–4 power level (e.g., 255 Ω for Class 4), and R(ILIM) = 178 kΩ programs 100–180 mA inrush current limit. The PG output asserts high-impedance only after successful classification and UVLO exit, with 75–225 µs deglitch timing.

Key Specifications

Pinout & Package

TPS2375DRG4 is packaged in an 8-pin SOIC (SO-8) with exposed pad, pin-compatible with industry-standard D (SOIC) footprint. Thermal resistance θ_JA = 238°C/W (low-K board) supports continuous 350 mA operation at 85°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS2375D, TPS2375DRG4 adds RoHS compliance and tape-and-reel readiness; compared with TPS2376PW, it trades UVLO programmability for SOIC-8 mechanical compatibility and simplified biasing-making it optimal for standard IEEE 802.3af deployments with fixed-threshold PSEs.

Availability

TPS2375DRG4 is available at Aetrix Electronics and suitable for VoIP phones, WLAN access points, and security cameras requiring stable component supply, long-term lifecycle support, and guaranteed green material compliance.

Supply support for TPS2375DRG4 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 leader specializing in analog, embedded processing, and connectivity technologies, with decades of leadership in power management and industrial interface solutions.

The TPS2375 family belongs to TI's Power over Ethernet product line, designed specifically to simplify IEEE 802.3af PD implementation with integrated switching, robust protection, and minimal external components.

FAQ

What is the primary function of the TPS2375DRG4 in a PoE system?

The TPS2375DRG4 serves as the IEEE 802.3af-compliant powered device (PD) controller, managing detection, classification, inrush current limiting, undervoltage lockout, and power-good signaling. It integrates a 0.58-Ω 100-V low-side MOSFET switch and interfaces directly with the PoE input diode bridge and downstream DC/DC converter. The TPS2375DRG4 ensures safe, standards-compliant power extraction from Ethernet cables while protecting against overcurrent, overtemperature, and ESD events.

Does the TPS2375DRG4 support Class 4 power classification per IEEE 802.3af?

Yes, the TPS2375DRG4 supports Class 4 classification using a 255 Ω ±1% resistor from CLASS pin to VSS, which draws 39.4 mA nominal during the 13–21 V classification window. This enables the PD to negotiate up to 12.95 W at its input, consistent with IEEE 802.3af Class 4 limits. The TPS2375DRG4's classification current accuracy and hysteresis ensure reliable PSE recognition without false classification or timeout.

What is the purpose of the ILIM pin on the TPS2375DRG4, and how is it configured?

The ILIM pin on the TPS2375DRG4 sets the inrush current limit during PoE startup by connecting an external resistor (R(ILIM)) to VSS. With R(ILIM) = 178 kΩ, the TPS2375DRG4 limits inrush to 100–180 mA, preventing input voltage sag that could trigger PSE current-limit shutdown. The resistor value must be between 62.5 kΩ and 500 kΩ; leaving ILIM open or shorted to VSS will disable inrush control and may damage the device or cause unreliable startup.

Can the TPS2375DRG4 be used with legacy PoE equipment that does not fully comply with IEEE 802.3af?

The TPS2375DRG4 is optimized for IEEE 802.3af-compliant PSEs with its fixed 30.5 V/39.3 V UVLO thresholds. For legacy systems requiring lower turn-on voltage or smaller hysteresis, Texas Instruments recommends the TPS2377 (legacy UVLO) or TPS2376 (programmable UVLO). Using TPS2375DRG4 with noncompliant PSEs may result in startup instability or failure to power up reliably under marginal voltage conditions.

What thermal protection features does the TPS2375DRG4 include?

The TPS2375DRG4 incorporates internal thermal shutdown that activates at 135°C junction temperature with 20°C hysteresis, forcing the device into a latched-off state until temperature falls below 115°C. This protects the integrated MOSFET and surrounding PCB during sustained overload or poor heatsinking. The SOIC-8 package's θ_JA = 238°C/W (low-K board) allows continuous 350 mA operation at 85°C ambient when properly laid out with adequate copper area.