MAX5971B

Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I²C

40W, I²C, Single-Port, IEEE 802.3af/at-Compliant PSE Controller with Integrated 0.5Ω Power MOSFET and Sense Resistor


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Description

The MAX5971B is a single-port power controller designed for use in IEEE® 802.3af/at-compliant power-sourcing equipment (PSE). This device provides powered device (PD) discovery, classification, current limit, and DC and AC load-disconnect detections. The MAX5971B supports both fully automatic operation and software programmability, and features an integrated power MOSFET and sense resistor. The device supports detection and classification operation from a single 54V supply. In addition, it supports 2-event classification and new Class 5 classification of high-power PDs. The MAX5971B provides up to 40W to a single port (Class 5 enabled) and still provides high-capacitance detection for legacy PDs.

The device provides four operating modes to suit different system requirements. By default, auto mode allows the device to operate automatically at its default settings without any software. Semi-automatic mode automatically detects and classifies a device connected to the port after initial software activation, but does not power the port until instructed to by software. Manual mode allows total software control of the device and is useful for system diagnostics. Shutdown mode terminates all port activities and securely turns off power to the port.

The IC features an I2C-compatible, 2-wire serial interface, and is fully software-configurable and programmable. The device provides instantaneous readout of port current through the I2C interface. The device’s extensive programmability enhances system flexibility, enables field diagnosis and allows for uses in other, non-standard applications.

The device provides input undervoltage lockout (UVLO), input undervoltage detection, input overvoltage lockout, overtemperature protection, output voltage slew-rate limit during startup, and LED status indication. The MAX5971B programmability includes startup timeout, overcurrent timeout, and load-disconnect detection timeout.

The device is available in a space-saving, 28-pin TQFN (5mm x 5mm) power package and is rated for the extended (-40°C to +85°C) temperature range.
MAX5971B: Typical Operating Circuit MAX5971B: Typical Operating Circuit Enlarge+

Key Features

  • IEEE 802.3af/at Compliant
  • Up to 40W for Single-Port PSE Applications
  • Integrated Power MOSFET and Sense Resistor
  • Supports 54V Single-Supply Operation
  • PD Detection and Classification
  • I2C-Compatible, 2-Wire Serial Interface
  • Instantaneous Readout of Port Current Through I2C Interface
  • Programmable Current Limit for Class 5 PDs
  • High-Capacitance Detection for Legacy Devices
  • Supports Both DC and AC Load Removal Detections
  • Current Foldback and Duty-Cycle-Controlled Current Limit
  • LED Indicator for Port Status
  • Direct Fast-Shutdown Control Capability
  • Space-Saving, 28-Pin TQFN (5mm x 5mm) Power Package

Applications/Uses

  • Single-Port PSE End-Point Applications
  • Single-Port PSE Power Injectors (Midspan Applications)
  • Switches/Routers
Part NumberComplianceHigh Power ModeChannelsPort Current ReadoutLoad DisconnectProgram-
mability
Package/PinsOper. Temp.
(°C)
Budgetary
Price
See Notes
MAX5971B 
IEEE 802.3af
IEEE 802.3at
Yes1I2CAC/DCI2C
TQFN/28
-40 to +85$4.53 @1k
See All Power Sourcing Equipment (8)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.


MAX5971BEVKIT: Evaluation Kit for the MAX5971B

Technical Documents

App Note 6161 PoE Power Injector

Quality and Environmental Data

Request Reliability Report for: MAX5971B 
Lead-Free Package Tin (Sn) Whisker Reports
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

Quality Management System >
Environmental Management System >

 
Status:
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Temperature:

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App Note 6161 PoE Power Injector