The TPS23881 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
TPS23881 improves on the TPS23880 with reduced current sense resistors, more
accurate programmable power limiting, capacitance measurement and the ability to
operate from ROM (see Device Comparison Table). The TPS23881 is also compatible with
TI’s FirmPSE system firmware, which provides a fully
configurable solution for controlling multiple TPS23881 devices in systems offering
up to 48-ports of 4-pair PoE power. Programmable SRAM enables in-field firmware upgradability over I 2C 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.
