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MAX5981B Datasheet Powered Device Interface Controllers

Manufacturer: Maxim Integrated (now Analog Devices)

Overview: MAX5981A/MAX5981B 19-5732; Rev 2; 8/11 IEEE 802.3af/at-Compliant, Powered Device Interface Controllers with Integrated Power MOSFET.

This datasheet includes multiple variants, all published together in a single manufacturer document.

General Description

The MAX5981 provides a com­plete interface for a powered device (PD) to comply with the IEEE® 802.3af/at standard in a power-over-ethernet (PoE) system.

The MAX5981 provides the PD with a detection signature, classifica­tion signature, and an integrated isolation power switch with inrush current control.

During the inrush period, the MAX5981 limits the current to less than 180mA before switching to the higher curr­ent limit (720mA to 880mA) when the isolation power MOSFET is fully enhanced.

Key Features

  • an input UVLO with wide hysteresis and long deglitch time to compensate for twisted-pair cable resistive drop and to assure glitch-free transition during power-on/-off condi­tions. The MAX5981 can with­stand up to 100V at the input. The MAX5981 supports a 2-Event classification method as specified in the IEEE 802.3at standard and provides a signal to indicate when probed by a Type 2 power sourcing equipment (PSE). The device detects the presence of a wall adapter power source connection and allo.

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