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Features and Benefits

  • Powered Device Interface
    • Fully Integrated IEEE 802.3af-Compliant PD Interface
    • PD Detection and Programmable Classification Signatures
    • Less than 10µA Leakage Current Offset During Detection
    • Integrated MOSFET for Isolation and Inrush Current Limiting
    • Gate Output Allows External Control of the Internal Isolation FET
    • Programmable Inrush Current Control/ULVO
    • PGOOD/Active-Low PGOOD Outputs Enable PWM Controller
  • PWM Controller
    • Wide Input Range: 18V to 67V
    • Isolated (Without Optocoupler) or Nonisolated Power Supply
    • Current-Mode Control
    • Leading-Edge Blanking
    • Internally Trimmed 275kHz ±10% Oscillator
    • Soft-Start

Product Details

The MAX5942A/MAX5942B integrate a complete power IC for powered devices (PD) in a power-over-ethernet (PoE) system. The MAX5942A/MAX5942B provide a PD interface and a compact DC-DC PWM controller suitable for flyback and forward converters in either isolated or nonisolated designs.

The MAX5942A/MAX5942B PD interface complies with the IEEE™ 802.3af standard, providing the PD with a detection signature, a classification signature, and an integrated isolation switch with programmable inrush current control. These devices also feature power-mode undervoltage lockout (UVLO) with wide hysteresis and power-good status outputs.

The MAX5942A/MAX5942B also integrate all the building blocks necessary for implementing DC-DC fixed-frequency isolated power supplies. This device is a current-mode controller with an integrated high startup circuit suitable for isolated telecom/industrial voltage range power supplies. A high-voltage startup circuit allows the PWM controller to draw power directly from the 18V to 67V input supply during startup. The switching frequency is internally trimmed to 275kHz ±10%, thus reducing magnetics and filter components. The MAX5942A allows an 85% operating duty cycle and can be used to implement flyback converters. The MAX5942B limits the operating duty cycle to less than 50% and can be used in single-ended forward converters. The MAX5942A/MAX5942B are designed to work with or without an external diode bridge in front of the PD.

The MAX5942A/MAX5942B are available in 16-pin SO packages.


  • Computer Telephony
  • Internet Appliances
  • IP Phones
  • Power Devices in Power-Over-Ethernet/Power-Over-MDI
  • Security Cameras
  • Wireless Access Nodes

Product Categories

Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Product Recommendations

MAX5942A Companion Parts

Recommended Related Parts

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.

Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
MAX5942ACSE+ Material Declaration Reliability Data 16-SOIC_N-150_MIL
Wafer Fabrication Data

Sample & Buy

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Buy Now Pricing

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List Pricing

(*)The 1Ku list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


Lead Times

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