The MAX5971B integrates a 0.5ohm power MOSFET, sense resistor, and current monitor to save space and cost in PSE systems--the typical application circuit requires fewer than eight external components. Additionally, the MAX5971B includes a 9-bit ADC and I2C interface to enable advanced power management and power budgeting. Capable of delivering up to 40 W/port for PoE+ powered devices (PDs), the MAX5971B is well suited for IP phones, IP cameras, wireless LAN access points, and video surveillance cameras.

This PSE controller is fully compliant to the IEEE 802.3af and IEEE 802.3at standards. The device operates from 32 V to 60 V and provides IEEE 802.3af/at-compliant PD discovery, classification, and DC/AC load-disconnect detection. Class 5 and two-event classification are supported for detection and classification of high-power PDs. The MAX5971B also detects legacy (noncompliant) PDs that use high capacitance as the discovery signature.

The device is fully software configurable through its I2C-compatible, 2-wire serial interface. The MAX5971B can be controlled with a system microcontroller (such as the MAXQ2000); it can be configured to operate autonomously without the need for a host microcontroller or software; or it can be configured to operate in manual or semiautomatic modes, which provide design flexibility as well as field debug and diagnostic capabilities.

Other device features include input undervoltage-lockout (UVLO) detection, input overvoltage detection, LED-status indication, overtemperature protection, and output voltage slew-rate limiting during startup.

Availability and Pricing

Production samples and evaluation (EV) kits are available. The MAX5971B is packaged in a 28-pin TQFN and is rated to operate over the -40  to +85 degrees Celsius extended temperature range. Price starts at 3.15 US Dollars (1000-up FOB USA).

Datasheet: MAX5971B