MAX5945

Obsolete

Quad Network Power Controller for Power-Over-LAN

Data Sheet (Rev. 1) Product Selection Table
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Overview

  • IEEE 802.3af Compliant
  • Controls Four Independent, -48V-Powered Ethernet Ports in Either Endpoint or Midspan PSE Applications
  • Wide Digital Power Input, VDIG, Common-Mode Range: VEE to (AGND + 7.7V)
  • PD Violation of Class Current Protection
  • PD Detection and Classification
  • Provides Both DC and AC Load Removal Detections
  • I²C-Compatible, 3-Wire Serial Interface
  • Fully Programmable and Configurable Operation Through I²C Interface
  • Current Foldback and Duty-Cycle-Controlled/Programmable Current Limit
  • Short-Circuit Protection with Fast Gate Pulldown
  • Direct Fast Shutdown Control Capability
  • Programmable Direct Interrupt Output
  • Watchdog Mode Enable Hardware Graceful Takeover

The MAX5945 quad network power controller is designed for use in IEEE® 802.3af-compliant power-sourcing equipment (PSE). The device provides power devices (PD) discovery, classification, current-limit, and both DC and AC load disconnect detections. The MAX5945 can be used in either endpoint PSE (LAN switches/routers) or midspan PSE (power injector) applications.

The MAX5945 can operate autonomously or be controlled by software through an I²C-compatible interface. Separate input and output data lines (SDAIN and SDAOUT) allow usage with optocouplers. The MAX5945 is a slave device. Its four address inputs allow 16 unique MAX5945 addresses. A separate active-low INT output and four independent shutdown inputs (active-low SHD_) allow fast response from a fault to port shutdown. An active-low RESET input allows hardware reset of the device. A special watchdog feature allows the hardware to gracefully take over control if the software crashes. A cadence timing feature allows the MAX5945 to be used in midspan systems.

The MAX5945 is fully software configurable and programmable. A class-overcurrent detection function enables system power management to detect if a PD draws more current than the allowable amount for its class. Other features are input under/overvoltage lockout, overtemperature protection, output-voltage slew-rate limit during startup, power-good, and fault status. The MAX5945's programmability includes gate-charging current, current-limit threshold, startup timeout, overcurrent timeout, autorestart duty cycle, PD disconnect AC detection threshold, and PD disconnect detection timeout.

The MAX5945 is available in a 36-pin SSOP package and is rated for both extended (-40°C to +85°C) and commercial (0°C to +70°C) temperature ranges.

Applications

  • Midspan Power Injector
  • Power-Over-LAN/Power-Over-Ethernet
  • Power-Sourcing Equipment (PSE)
  • Switches/Routers
MAX5945
Quad Network Power Controller for Power-Over-LAN
MAX5945: Typical Operating Circuit
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Documentation

Data Sheet 1

Reliability Data 1

Technical Articles 2

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Evaluation Kits

MAX5945EVSYS

Evaluation Kit/Evaluation System for the MAX5945

Buy Now View Details

Features and Benefits

  • IEEE 802.3af-Compliant Power-Sourcing Equipment (PSE) Circuit
  • Input Voltages
    • -32V to -60V Providing 2A (-48V Power Circuit, 350mA/Port)
    • +3.3V Providing 100mA (Digital Logic Power)
    • VCC (+3.3V) Provides 100mA (Optical Interface)
    • +9V Provides 250mA (SMBus LPT Interface Board)
  • Ethernet Network Ports
    • Four RJ-45 10/100 Base-TX Ethernet Network Input Ports
    • Four RJ-45 10/100 Base-TX Ethernet Network Output Power-Over-Ethernet Ports
  • Demonstrates Four Separate Independent Power Switch Controllers
  • Provides PD Detection and Classification
  • Configurable DC/AC Load Removal Detection and Disconnect Monitoring
  • Configurable Current Sensing
  • Convenient Voltage and Current Test Points
  • Four Output-Port LED Status Indicators
  • Optically Isolated 3-Wire I²C-Compliant PC Interface
  • Reconfigurable for Stand-Alone Operation or with External Microcontroller
  • Windows 95/98/2000-Compatible Software
  • Fully Assembled and Tested

Product Details

The MAX5945 evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board featuring an Ethernet four-port network power controller circuit for -48V supply rail systems. The MAX5945 IEEE 802.3af-compliant network power controller is available in a 36-pin SSOP package. The circuit includes four n-channel power MOSFETs used to form the main power-sourcing equipment (PSE) circuit on the EV kit. The MAX5945 is used in power-over-ethernet (POE) applications requiring DC power over four Ethernet network ports. The EV kit provides optical isolation for the I²C-compliant 3-wire interface. The isolated interface connects to a PC parallel port (LPT) through a MAXSMBus interface board. The EV kit can easily be reconfigured for interfacing to a user's stand-alone microcontroller for isolated or nonisolated operation.

The MAX5945 EV kit requires a -32V to -60V power supply (-48V supply rail) capable of supplying 2A or more to the EV kit for powering the power device (PD) through the four 10/100 base-TX Ethernet network ports. The EV kit demonstrates PD discovery, classification, current-limit control and other functions of an IEEE 802.3af-compliant PSE. The user must also supply two separate 3.3V power supplies capable of supplying 100mA for the EV kit's digital logic and 3.3V (VCC) optically isolated 3-wire interface. The MAXSMBus interface board requires a dedicated 9V power supply capable of supplying 250mA. The +9V power supply is not required for nonisolated operation.

The MAX5945 controls the -48V DC power to each of the four Ethernet network ports by controlling each port's power MOSFET and sensing current through the respective port's current-sense resistor. The current is fed to a 10/100 base-TX Voice-over-IP (VoIP) magnetic module at each Ethernet network output port. The MAX5945 EV kit provides a separate independent power channel for each of the four Ethernet network output ports.

The EV kit demonstrates the full functionality of the MAX5945 for each power channel such as configurable operational modes, PD detection, PD classification, overcurrent protection, current foldback, under/overvoltage protection, and AC disconnect monitoring. All of these features are configurable on the EV kit and additional test points for voltage probing and current measurements have been provided.

Applications

  • Midspan Power Injector
  • Power-Over-LAN/Power-Over-Ethernet
  • Power-Sourcing Equipment (PSE)
  • Switches/Routers

MAX5945EVKIT

Evaluation Kit/Evaluation System for the MAX5945

Buy Now View Details

Features and Benefits

  • IEEE 802.3af-Compliant Power-Sourcing Equipment (PSE) Circuit
  • Input Voltages
    • -32V to -60V Providing 2A (-48V Power Circuit, 350mA/Port)
    • +3.3V Providing 100mA (Digital Logic Power)
    • VCC (+3.3V) Provides 100mA (Optical Interface)
    • +9V Provides 250mA (SMBus LPT Interface Board)
  • Ethernet Network Ports
    • Four RJ-45 10/100 Base-TX Ethernet Network Input Ports
    • Four RJ-45 10/100 Base-TX Ethernet Network Output Power-Over-Ethernet Ports
  • Demonstrates Four Separate Independent Power Switch Controllers
  • Provides PD Detection and Classification
  • Configurable DC/AC Load Removal Detection and Disconnect Monitoring
  • Configurable Current Sensing
  • Convenient Voltage and Current Test Points
  • Four Output-Port LED Status Indicators
  • Optically Isolated 3-Wire I²C-Compliant PC Interface
  • Reconfigurable for Stand-Alone Operation or with External Microcontroller
  • Windows 95/98/2000-Compatible Software
  • Fully Assembled and Tested

Product Details

The MAX5945 evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board featuring an Ethernet four-port network power controller circuit for -48V supply rail systems. The MAX5945 IEEE 802.3af-compliant network power controller is available in a 36-pin SSOP package. The circuit includes four n-channel power MOSFETs used to form the main power-sourcing equipment (PSE) circuit on the EV kit. The MAX5945 is used in power-over-ethernet (POE) applications requiring DC power over four Ethernet network ports. The EV kit provides optical isolation for the I²C-compliant 3-wire interface. The isolated interface connects to a PC parallel port (LPT) through a MAXSMBus interface board. The EV kit can easily be reconfigured for interfacing to a user's stand-alone microcontroller for isolated or nonisolated operation.

The MAX5945 EV kit requires a -32V to -60V power supply (-48V supply rail) capable of supplying 2A or more to the EV kit for powering the power device (PD) through the four 10/100 base-TX Ethernet network ports. The EV kit demonstrates PD discovery, classification, current-limit control and other functions of an IEEE 802.3af-compliant PSE. The user must also supply two separate 3.3V power supplies capable of supplying 100mA for the EV kit's digital logic and 3.3V (VCC) optically isolated 3-wire interface. The MAXSMBus interface board requires a dedicated 9V power supply capable of supplying 250mA. The +9V power supply is not required for nonisolated operation.

The MAX5945 controls the -48V DC power to each of the four Ethernet network ports by controlling each port's power MOSFET and sensing current through the respective port's current-sense resistor. The current is fed to a 10/100 base-TX Voice-over-IP (VoIP) magnetic module at each Ethernet network output port. The MAX5945 EV kit provides a separate independent power channel for each of the four Ethernet network output ports.

The EV kit demonstrates the full functionality of the MAX5945 for each power channel such as configurable operational modes, PD detection, PD classification, overcurrent protection, current foldback, under/overvoltage protection, and AC disconnect monitoring. All of these features are configurable on the EV kit and additional test points for voltage probing and current measurements have been provided.

Applications

  • Midspan Power Injector
  • Power-Over-LAN/Power-Over-Ethernet
  • Power-Sourcing Equipment (PSE)
  • Switches/Routers
MAX5945EVSYS
Evaluation Kit/Evaluation System for the MAX5945
MAX5945EVKIT
Evaluation Kit/Evaluation System for the MAX5945

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