The LM5070 power interface port and pulse width modulation (PWM) controller provides a complete integrated solution for Powered Devices (PD) that connect into Power over Ethernet (PoE) systems. The LM5070 integrates an 80V, 400mA line connection switch and associated control for a fully IEEE 802.3af compliant interface with a full featured current mode pulse width modulator dc-dc converter. All power sequencing requirements between the controller interface and switch mode power supply (SMPS) are integrated into the IC. Two options are available providing either an 80% maximum duty cycle limit with slope compensation (on the 80 suffix) device or a 50% maximum duty cycle limit and no slope compensation on the (50 suffix) device.