Power Over Ethernet PD Controller with Auxiliary Power Interface - LM5071


Power Over Ethernet PD Controller with Auxiliary Power Interface


Recommended alternative parts

  • LM5070  -  Integrated Power Over Ethernet PD Interface And PWM Controller
  • LM5072  -  Higher Transient Voltages (100V), Supplies More Current (750mA) And Compatible With Auxiliary Power


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.


  • 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)


  • TSSOP-16

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Parametrics Compare all products in Powered Device

Vin (Min) (V)
Vin (Max) (V)
PoE Current Limit (Min) (mA)
PoE Inrush Limit (Typ) (mA)
rDS(on) per FET (Typ) (mOhms)
PoE Standards Supported
PD Power Level
DC/DC Control
Fault Response
Special Features
Package Group
Package Size: mm2:W x L (PKG)
Switching Frequency
LM5071 LM5070 LM5072
1.8    1.8    9   
60    75    70   
390    300    800   
100    Programmable    Programmable   
1000    1000    700   
802.3at Type 1 (802.3af)    802.3at Type 1 (802.3af)    802.3at Type 1 (802.3af)   
13W    13W    25W   
PD and DC/DC    PD and DC/DC    PD and DC/DC   
Thermal Cycling    Thermal Cycling    Thermal Cycling   
Error Amplifier
Programmable UVLO
Thermal Shutdown   
Error Amplifier
Programmable UVLO
Thermal Shutdown   
Error Amplifier
Thermal Shutdown   
16TSSOP: 32 mm2: 6.4 x 5(TSSOP)    See datasheet (WSON)    16HTSSOP: 22 mm2: 4.4 x 5(HTSSOP)   

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