Analog Devices Inc.

Category: Drivers and Interfaces

The MAX5942A/MAX5942B integrate a complete powerIC for powered devices (PD) in a power-over-ethernet(PoE) system. The MAX5942A/MAX5942B provide a PDinterface and a compact DC-DC PWM controller suitablefor flyback and forward converters in either isolated ornonisolated designs.The MAX5942A/MAX5942B PD interface complies withthe IEEE™ 802.3af standard, providing the PD with adetection signature, a classification signature, and anintegrated isolation switch with programmable inrush currentcontrol. These devices also feature power-modeundervoltage lockout (UVLO) with wide hysteresis andpower-good status outputs.The MAX5942A/MAX5942B also integrate all the buildingblocks necessary for implementing DC-DC fixed-frequencyisolated power supplies. This device is acurrent-mode controller with an integrated high startupcircuit suitable for isolated telecom/industrial voltagerange power supplies. A high-voltage startup circuitallows the PWM controller to draw power directly from the18V to 67V input supply during startup. The switchingfrequency is internally trimmed to 275kHz ±10%, thusreducing magnetics and filter components. TheMAX5942A allows an 85% operating duty cycle and canbe used to implement flyback converters. The MAX5942Blimits the operating duty cycle to less than 50% and canbe used in single-ended forward converters. TheMAX5942A/MAX5942B are designed to work with or withoutan external diode bridge in front of the PD.The MAX5942A/MAX5942B are available in 16-pin SOpackages.ApplicationsComputer TelephonyInternet AppliancesIP PhonesPower Devices in Power-Over-Ethernet/Power-Over-MDISecurity CamerasWireless Access Nodes

* $4.41 - $8.54