LM5070 Datasheet, PDF (1/17 Pages) National Semiconductor (TI) – Integrated Power Over Ethernet PD Interface and PWM Controller

December 2004
LM5070
Integrated Power Over Ethernet PD Interface and PWM
Controller
General Description
The LM5070 power interface port and pulse width modula-
tion (PWM) controller provides a complete integrated solu-
tion 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 in-
terface and switch mode power supply (SMPS) are inte-
grated 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.
Features
n Fully Compliant 802.3af Power Interface Port
n 80V, 1Ω, 400 mA Internal MOSFET
n Programmable Inrush Current Limit
n Detection Resistor Disconnect Function
n Programmable Classification Current
n Programmable Under-voltage Lockout with
Programmable Hysteresis
n Thermal Shutdown Protection
n Current Mode Pulse Width Modulator
n Supports both Isolated and Non-Isolated Applications
n Error Amplifier and Reference for Non-Isolated
Applications
n Programmable Oscillator Frequency
n Programmable Soft-start
n 80% Maximum Duty Cycle Limiter, Slope Compensation
(-80 device)
n 50% Maximum Duty Cycle Limiter, No Slope
Compensation (-50 device)
n 800 mA Peak Gate Driver
Packages
n TSSOP-16
n LLP-16 (5 mm x 5 mm)
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