Datasheet
Table Of Contents
- FEATURES
- Packages
- DESCRIPTION
- Absolute Maximum Ratings
- Operating Ratings
- Electrical Characteristics
- Typical Performance Characteristics
- Specialized Block Diagrams
- Detailed Operating Description
- Modes of Operation
- Detection Signature
- Classification
- Undervoltage Lockout (UVLO)
- AUX Pin Operation
- Power Supply Operation
- High Voltage Start-up Regulator
- Error Amplifier
- Current Limit / Current Sense
- Oscillator, Shutdown and Sync Capability
- PWM Comparator / Slope Compensation
- Soft-Start
- Gate Driver and Maximum Duty Cycle Limit
- Thermal Protection
- LM5071 Application Circuit Diagrams
- Revision History
DC - DC
Converter
PWM Controller
Current Mode
IEEE 802.3af Interface
UVLO
Signature Detection
Classification
VOUT
Feedback
+
_
AUX
AC
Adapter
Jack
Auxiliary
Power
Enable
PoE (+)
PoE (-)
Hot Swap
In-rush and Fault
Current Limiting
LM5071
LM5071
www.ti.com
SNVS409E –NOVEMBER 2005–REVISED APRIL 2013
LM5071 Power Over Ethernet PD Controller with Auxiliary Power Interface
Check for Samples: LM5071
1
FEATURES
PACKAGES
2
• Compatible with 12V AC Adapters
• TSSOP-16
• Fully Compliant 802.3af Power Interface Port
DESCRIPTION
• 80V, 1Ω, 400 mA Internal MOSFET
The LM5071 power interface port and pulse width
• Detection Resistor Disconnect Function
modulation (PWM) controller provides a complete
• Programmable Classification Current
integrated solution for Powered Devices (PD) that
connect into Power over Ethernet (PoE) systems.
• Programmable Under-voltage Lockout with
The LM5071 is specifically designed for the PD
Programmable Hysteresis
that must accept power from auxiliary sources
• Thermal Shutdown Protection
such as AC adapters. The auxiliary power interface
• Auxiliary Power Enable Pin
of the LM5071 activates the PWM controller when the
ac adapter is connected to power the PD when PoE
• Current Mode Pulse Width Modulator
network power is unavailable. The LM5071 integrates
• Supports both Isolated and Non-Isolated
an 80V, 400mA line connection switch and
Applications
associated control for a fully IEEE 802.3af compliant
• Error Amplifier and Reference for Non-Isolated
interface with a full featured current mode pulse width
Applications
modulator dc-dc converter. All power sequencing
requirements between the controller interface and
• Programmable Oscillator Frequency
switch mode power supply (SMPS) are integrated into
• Programmable Soft-Start
the IC.
• 80% Maximum Duty Cycle Limiter, Slope
Compensation (-80 device)
• 50% Maximum Duty Cycle Limiter, No Slope
Compensation (-50 device)
Block Diagram
1
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PRODUCTION DATA information is current as of publication date.
Copyright © 2005–2013, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.