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. Applications * Computer Telephony * Internet Appliances * IP Phones * Power Devices in Power-Over-Ethernet/Power-Over-MDI * Security Cameras * Wireless Access Nodes * 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 https://elecena.pl/product/22330413/ieee-802-3af-power-over-ethernet-interface-pwm-controller-for-power-devices 2022-12-28 https://elecena.pl/product/22330413/ieee-802-3af-power-over-ethernet-interface-pwm-controller-for-power-devices 2024-03-25