Analog Devices MAX5992A Product Info

• IEEE 802.3af/at Compliant
• UPoE Compatible
• High-Power 2x2P/Multi-PD Synchronization/Multi-PD Redundancy
• Integrated Active FET Bridge Control and Back-Powering Protection
• Selectable UVLO for Medical/Industrial Applications
• 2-Level Inrush-Current Control
• Intelligent MPS
• Simplified Wall Adapter Interface for Seamless Power Transition
• Ultra-Low-Power/Sleep Mode
• 2-Event Classification or an External Wall Adapter Indicator Output
• PoE Classification 0 to 5
• Gate Driver for External Isolation MOSFET
• Selectable Current Limit and Foldback
• RJ45 12V Supply Input
• 6.5s Sleep Mode Delay

The MAX5992A/MAX5992B multisource, high-power, high-performance powered device (PD) controllers provide a complete interface control for PDs to comply with the IEEE^® 802.3af/at standard in a Power-over-Ethernet (PoE) system. The devices provide the PD with a detection signature, classification signature, and an isolation MOSFET driver with current-limit control. In addition, the intelligent maintain power signature (MPS) and active FET bridge control make the PD more power efficient. The devices feature a active-low SIG_OK output signal for high-power Multi-2P PD applications. The selectable inrush-current modes allow Multi-PD, fiber-to-the-home/fiber-to-the-building (FTTH/FTTB) operation in redundancy applications. The devices feature an input UVLO, wide hysteresis, and long deglitch time to compensate for twisted-pair cable resistive drop to assure glitch-free transition during power-on/power-off conditions. The devices can operate from a 20.8V low-voltage supply by a selectable UVLO. The devices can withstand up to 100V at the input.

The devices support a 2-Event classification method as specified in the IEEE 802.3at standard and provide a signal to indicate when probed by Type 2 power-sourcing equipment (PSE). The devices detect the presence of a wall adapter power-source connection and allow a smooth switchover from the PoE power source to the wall power adapter. Moreover, the selectable WAD_SEL supports seamless power transition from a wall adapter to PoE if PoE is already enabled.

The devices also provide a power-good (PG) signal, 2-level current limit, foldback, and overtemperature protection. A sleep mode feature provides low-power consumption while supporting MPS. An ultra-low power sleep mode feature further reduces power consumption to comply with ultra-low power requirements while still supporting MPS. The devices also feature an LED driver that is automatical