TPS23881B中文資料德州儀器數據手冊PDF規(guī)格書

1 Features

? IEEE 802.3bt PSE solution for PoE 2 Type 3 or

Type 4 Power over Ethernet applications

? Eight independent PSE channels

? Resistor selectable Autonomous operation

– No external MCU required

? Compatible with TI's FirmPSE system firmware

? SRAM Programmable memory

? Programmable power limiting accuracy ±2.5

? 200mΩ current sense resistor

? Legacy PD capacitance measurement

? Selectable 2-pair or 4-pair port power allocations

– 15.4W, 30W, 45W, 60W, 75W or 90W

? Single and dual signature PD compatibility

? Dedicated 14-bit integrating current ADC per port

– Noise immune MPS for DC disconnect

– 2 current sensing accuracy

? 1- or 3-bit fast port shutdown input

? Auto-class discovery and power measurement

? Inrush and operational foldback protection

? Flexible processor controlled operating modes

– Auto, semi auto and manual / diagnostic

? Per port voltage monitoring and telemetry

? –40°C to +125°C temperature operation

? Ultra Low Alpha (ULA) packaging (TPS23881A)

2 Applications

? Video recorder (NVR, DVR, and so forth)

? Small business switch

? Campus and branch switches

3 Description

The TPS23881B is an 8-channel power sourcing

equipment (PSE) controller engineered to insert

power onto Ethernet cables in accordance with the

IEEE 802.3bt standard. The eight individual power

channels can be configured in any combination of

2-Pair (1-channel) or 4-Pair (2-channels) PoE Ports.

The PSE controller can detect powered devices

(PDs) that have a valid signature, complete mutual

identification, and apply power.

The TPS23881B improves on the TPS2388

with reduced current sense resistors, selectable

Autonomous operation, SRAM programmability,

programmable power limiting, capacitance

measurement, and compatibility with TI's FirmPSE

system firmware (see Device Comparison Table).

Programmable SRAM enables in-field firmware

upgradability over I2C to ensure IEEE compliance and

interoperability with the latest PoE enabled devices.

Dedicated per port ADCs provide continuous port

current monitoring and the ability to perform parallel

classification measurements for faster port turn on

times. A ±2.5 accurate programmable port power

limit provides the ability to expand the maximum

power sourced from 90 W to upwards of 125 W.

The 200-mΩ current sense resistor and external FET

architecture allow designs to balance size, efficiency,

thermal and solution cost requirements.