The MAX5996A/MAX5996B/MAX5996C provides a complete interface for a powered device (PD) to comply with the IEEE^® 802.3af/at/bt standard in a Power-Over-Ethernet (PoE) system with a detection signature, classification signature, and an integrated power switch with startup inrush current control. During the startup period, the devices limit the current to 135mA and it switches to a higher current limit when the power MOSFET is fully enhanced. The devices feature a Multi-Event classification, Intelligent MPS, Autoclass, and an input UVLO with wide hysteresis and deglitch time to assure glitch-free transition during power-on/off. The devices can withstand a maximum voltage of 100V at the input.

The devices can detect the presence of a wall adapter power and allow a smooth switch-over from the PoE power source to the wall adapter. The devices also provide a power-good (PG) signal, two-step current limit, and foldback control, overtemperature protection.

The Intelligent Maintain Power Signature (IMPS) feature allows to automatically enable MPS current by detecting the port current. Autoclass feature is to enable advanced applications that allow the PSE to optimize power allocation to PD.

When working with dc-dc controller IC, the MAX5996C features a constant power/current limit when the port power/current consumption reaches PSE power/current limit. Multi-Event indication feature provides patterned signals to indicate power level allocated from PSE to PD in 7 different scenarios, and accurate real-time power telemetry reporting. LLDP pin of the MAX5996C allows to read power/current limit configuration from system microcontroller and overwrite power/current limit from classification process.

The MAX5996A/MAX5996B/MAX5996C are available in a 16-pin, 5mm x 5mm, TQFN power package. These devices are rated over the -40°C to 125°C temperature range.

Applications

• Building Automation
• IEEE 802.3bt Powered Devices
• Lighting
• Small Cell, Pico Cell
• VOIP Phones, IP Security Cameras
• Wireless Access Point