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Quad Network Power Controller for Power-Over-LAN

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • 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

Applications/Uses

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

Description

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.

Simplified Block Diagram

MAX5945: Typical Operating Circuit MAX5945: 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 .