MAX5942B

19-3024; Rev 0; 10/03 MAX5942A/MAX5942B IEEE 802.3af Power-Over-Ethernet Interface/PWM Controller for Power Devices General Description 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 powergood status outputs. The MAX5942A/MAX5942B also integrate all the building blocks necessary for implementing DC-DC fixedfrequency isolated power supplies. This device is a current-mode controller with an integrated high startup circuit suitable for isolate...