LM5072 Datasheet, PDF (1/34 Pages) National Semiconductor (TI) – Integrated 100V Power Over Ethernet PD Interface and PWM Controller with Aux Support

LM5072
www.ti.com
SNVS437D – MARCH 2006 – REVISED APRIL 2013
LM5072 Integrated 100V Power Over Ethernet PD Interface and PWM Controller with Aux
Support
Check for Samples: LM5072
FEATURES
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•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)
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)
APPLICATIONS
• IEEE 802.3af Compliant PoE Powered Devices
• Non-Compliant, Application Specific Devices
• Higher Power Ethernet Powered Devices
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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