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IEEE 802.3af/at-Compliant, Powered Device Interface Controller with Integrated Power MOSFET

100V, 30W IEEE 802.3af/at PD Interface Controller

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • IEEE 802.3af/at Compliant
  • 2-Event Classification or an External Wall Adapter Indicator Output
  • Simplified Wall Adapter Interface
  • PoE Classification 0 to 5
  • 100V Input Absolute Maximum Rating
  • Inrush Current Limit of 180mA Maximum
  • Current Limit During Normal Operation Between 720mA and 880mA
  • Current Limit and Foldback
  • Legacy UVLO at 36V
  • Overtemperature Protection
  • Thermally Enhanced, 5mm x 5mm, 16-Pin TQFN

Applications/Uses

  • IEEE 802.3af/at Powered Devices
  • IP Phones, Wireless Access Nodes, IP Security Cameras
  • WiMAX™ Base Station

Description

The MAX5972A 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 MAX5972A provides the PD with a detection signature, classification signature, and an integrated isolation power switch with inrush current control. During the inrush period, the MAX5972A 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. The device 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 MAX5972A can withstand up to 100V at the input.

The MAX5972A supports a 2-event classification method as specified in the IEEE 802.3at standard and provides a signal to indicate when probed by Type 2 power-sourcing equipment (PSE). The device detects the presence of a wall adapter power-source connection and allows a smooth switch over from the PoE power source to the wall power adapter.

The MAX5972A also provides a power-good (PG) signal, two-step current limit and foldback, overtemperature protection, and di/dt limit.

The MAX5972A is available in a 16-pin, 5mm x 5mm, TQFN power package. This device is rated over the -40°C to +85°C extended temperature range.

Simplified Block Diagram

MAX5972A: Typical Operating Circuit MAX5972A: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .