"Microsemi's PD69101 is a single port, mixed-signal, high-voltage Power over Ethernet driver. The device is utilized in Ethernet switches and enables network devices to share power and data over the same cable. It enables detection of IEEE802.3af-2003 compliant PDs (Powered Devices) and IEEE802.3at High Power Devices ensuring safe power feeding and disconnection of ports with full digital control and a minimum of external components. Integrating power, analog and state of the art logic, the PD69101 device fits into a single 24-pin, plastic QFN package. A “plug and play” device, the PD69101 executes all real time functions as specified in the IEEE802.3af-2003 (“AF”) and IEEE802.3at High Power (“AT”) standards, including load detection, “AF” and “AT” classification, and using Multiple Classification Attempts (MCA). The PD69101 is designed to detect and disable disconnected ports, utilizing DC disconnection methods, as specified in the IEEE 802.3af-2003 and IEEE802.3at-2009 standards.It can optionally detect legacy/pre-standard PD devices. The PD69101 also provides PD protection such as over-load, under-load, over-voltage, over-temperature and short-circuiting. It supports supply voltages ranging from 44 V to 57 VDC with no need for additional power supply sources. The PD69101 is a low power device using an internal 0.34ohm MOSFET and an external 0.5ohm sense resistor. The chip includes built-in internal thermal protection. Two LEDs provide port state's indication and port type (AF/AT)."