Electronic Design

PoE Chip Delivers High Power Over Multiport Systems

Integrating several key components onto one chip (see the Figure), the TPS23841 quad-port Power-over-Ethernet (PoE) IC allows multiport enterprise systems to deliver up to 25 W over a standard Ethernet cable. That's nearly twice the power as previous IEEE 802.3af-compliant systems, according to the IC's manufacturer, Texas Instruments. With an operating range of -40°C to 125°C, the TPS23841 safely supplies up to 665 mA per port from input voltages of 21.5 to 57 V. The wide input voltage range enables designers to support emerging Ethernet-powered 24-V medical and industrial applications.

The device simplifies PoE design by integrating key components, including switches, sense resistors, and four individual 15-bit analog-to-digital converters (ADCs). The ADCs permit the chip to accurately measure signature resistance, voltage, current, and die temperature. The IC can also be used 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 offers three mode options—automatic, semi-automatic, and manual—giving the designer added flexibility to meet specific requirements. In manual mode, the device can work with a microcontroller, such as TI's MSP430 ultra-low-power MCU, to detect legacy capacitance loads.

The TPS23841 power manager is available in volume from TI and authorized distributors in a 64-pin high-temperature quad flat pack (HTQFP) package. Suggested resale price is $7.50 in quantities of 1000.

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Texas Instruments

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