The MAX5945 quad network power controller is designed for use in IEEE 802.3af-compliant power-sourcing equipment (PSE). The device provides power devices (PD) discovery, classification, current-limit, and both DC and AC load disconnect detections. The MAX5945 can be used in either endpoint PSE (LAN switches/routers) or midspan PSE (power injector) applications. The MAX5945 is pin and function compatible with LTC4259A. The MAX5945 can operate autonomously or be controlled by software through an I2C*-compatible interface. Separate input and output data lines (SDAIN and SDAOUT) allow usage with optocouplers. The MAX5945 is a slave device. Its four address inputs allow 16 unique MAX5945 addresses. A separate INT output and four independent shutdown inputs (SHD_) allow fast response from a fault to port shutdown. A RESET input allows hardware reset of the device. A special watchdog feature allows the hardware to gracefully take over control if the software crashes. A cadence timing feature allows the MAX5945 to be used in midspan systems.