1FEATURES

2• PD Interface

– Fully Compliant IEEE 802.3af PD Interface

– Versatile Auxiliary Power Options

– 9V Minimum Auxiliary Power Operating

Range

– 100V Maximum Input Voltage Rating

– Programmable DC Current Limit Up To

800mA

– 100V, 0.7Ω Hot Swap MOSFET

– Integrated PD Signature Resistor

– Integrated PoE Input UVLO

– Programmable Inrush Current Limit

– PD Classification Capability

– Power Good Indicator

– Thermal Shutdown Protection

• PWM Controller

– Current Mode PWM Controller

– 100V Start-Up Regulator

– Error Amplifier with 2% Voltage Reference

– Supports Isolated and Non-Isolated

Applications

– Programmable Oscillator Frequency

– Programmable Soft-Start

– 800 mA Peak Gate Driver

– 80% Maximum Duty Cycle with Built-in

Slope Compensation (-80 Device)

– 50% Maximum Duty Cycle, No Slope

Compensation (-50 Device)

APPLICATIONS

• IEEE 802.3af Compliant PoE Powered Devices

• Non-Compliant, Application Specific Devices

• Higher Power Ethernet Powered Devices

DESCRIPTION

The LM5072 Powered Device (PD) interface and

Pulse-Width-Modulation (PWM) controller provides a

complete power solution, fully compliant to IEEE

802.3af, for the PD connecting into Power over

Ethernet (PoE) networks. This controller integrates all

functions necessary to implement both a PD powered

interface and DC-DC converter with a minimum

number of external components. The LM5072

provides the flexibility for the PD to also accept power

from auxiliary sources such as AC adapters in a

variety of configurations. The low RDS(ON) PD

interface hot swap MOSFET and programmable DC

current limit extend the range of LM5072 applications

up to twice the power level of 802.3af compliant PD

devices. The 100V maximum voltage rating simplifies

selection of the transient voltage suppressor that protects the PD from network transients. The LM5072

includes an easy-to-use PWM controller that

facilitates the various single-ended power supply

topologies including the flyback, forward and buck.

The PWM control scheme is based on peak current

mode control, which provides inherent advantages

including line feed-forward, cycle-by-cycle current

limit, and simplified feedback loop compensation.

Two versions of the LM5072 provide either an 80%

maximum duty cycle (-80 suffix), or a 50% maximum

duty cycle (-50 suffix).

PACKAGES

• TSSOP-16 EP (Exposed Pad)