1FEATURES
2• Compatible with 12V AC Adapters
• Fully Compliant 802.3af Power Interface Port
• 80V, 1Ω, 400 mA Internal MOSFET
• Detection Resistor Disconnect Function
• Programmable Classification Current
• Programmable Under-voltage Lockout with
Programmable Hysteresis
• Thermal Shutdown Protection
• Auxiliary Power Enable Pin
• Current Mode Pulse Width Modulator
• Supports both Isolated and Non-Isolated
Applications
• Error Amplifier and Reference for Non-Isolated

Applications
• Programmable Oscillator Frequency
• Programmable Soft-Start
• 80% Maximum Duty Cycle Limiter, Slope
Compensation (-80 device)
• 50% Maximum Duty Cycle Limiter, No Slope
Compensation (-50 device)

PACKAGES
• TSSOP-16

DESCRIPTION
The LM5071 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 LM5071 is specifically designed for the PD
that must accept power from auxiliary sources
such as AC adapters. The auxiliary power interface
of the LM5071 activates the PWM controller when the
ac adapter is connected to power the PD when PoE
network power is unavailable. The LM5071 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.