High-power PoE manager targets multi-port systems

Texas Instruments Incorporated (TI) introduces the industry's first fully integrated Power over Ethernet (PoE) management device that allows multi-port enterprise systems to deliver up to 25 watts of power over a standard Ethernet cable. Supporting operation at -40° to +125°C, the power source equipment (PSE) manager enables commercial, industrial, medical and military applications to manage Ethernet-powered devices using nearly twice the power as previous IEEE 802.3af-compliant systems.

TI's TPS23841 quad-port PoE integrated circuit (IC) provides power management control and protection, while safely delivering up to 665 mA per port from input voltage levels of 21.5 V to 57 V. The device's extremely wide input voltage capability allows designers to support emerging Ethernet-powered 24-V medical and industrial applications, such as nurse call center systems and human machine-interaction equipment.

The TPS23841 simplifies PoE design by integrating several key components onto a single chip, including integrated switches and sense resistors and four individual 15-bit analog-to-digital (A/D) converters, which allows the device to accurately measure signature resistance, voltage, current and die temperature. The device also can be designed together with TI's TPS2384 power source equipment manager to enable high power and standard PoE operation in a system running on the same comprehensive software. The TPS23841 also provides three different options — automatic mode, semi-auto mode or manual operation — that give designers added flexibility to meet specific PoE system requirements. While in manual mode, the TPS23841 can work with a microcontroller, such as TI's MSP430 ultra-low-power microcontroller, to detect legacy capacitance loads.

The TPS23841 high-power PoE device matches all power requirements of TI's recently introduced 8-pin, TPS2376-H controller for Ethernet-powered devices. The high-power device controller contains all of the safety features needed to develop a powered device with programmable, 600-mA current limit and thermal shutdown, auto-retry and fault protection. The TPS2376-H also allows a designer to implement a non-standard powered device that draws up to 26 watts of power from power source equipment with a minimum of 52 volts of input and over 100 meters of CAT-5 Ethernet cable. The PD controller and the TPS23841 manager are both compatible with the most recent decisions of the IEEE 802.3at committee, which is responsible for defining the emerging PoE+ standard.

TI provides IEEE 802.3af-compliant powered device controllers and power sourcing equipment manager ICs, which manage power in multiple Ethernet ports. Leveraging its volume production capabilities and systems expertise, the company has shipped PoE circuits to a broad base of customers around the world. TI is a founding member of the PoETec Consortium and University of New Hampshire's PoE Consortium, and TI chairs the High-Power PoE+ task force in the IEEE 802.3at standards committee.

The TPS23841 power manager is available in volume today from TI and its authorized distributors. The device is packaged in a 64-pin HTQFP package. Suggested resale pricing is $7.50 in quantities of 1,000 units. Reference designs featuring the TPS2376-H and TPS23841, application notes and technical documentation are available through

Texas Instruments Incorporated Semiconductor Group, SC-06238 Literature Response Center 14950 FAA Blvd. Ft. Worth, TX 76155 1-800-477-8924

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