LM5071MT-50 NSC [National Semiconductor], LM5071MT-50 Datasheet

no-image

LM5071MT-50

Manufacturer Part Number
LM5071MT-50
Description
Power Over Ethernet PD Controller with Auxiliary Power Power Over Ethernet PD Controller with Auxiliary Power
Manufacturer
NSC [National Semiconductor]
Datasheet

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LM5071MT-50
Manufacturer:
NS
Quantity:
91
Part Number:
LM5071MT-50
Manufacturer:
NS/国半
Quantity:
20 000
Part Number:
LM5071MT-50/NOPB
Manufacturer:
NS
Quantity:
4 938
Part Number:
LM5071MT-50/NOPB
Manufacturer:
NS
Quantity:
28 000
© 2005 National Semiconductor Corporation
LM5071
Power Over Ethernet PD Controller with Auxiliary Power
Interface
General Description
The LM5071 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 LM5071 is specifically de-
signed for the PD that must accept power from auxiliary
sources such as ac adapters. The auxiliary power inter-
face 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 in-
terface and switch mode power supply (SMPS) are inte-
grated into the IC.
Features
n Compatible with 12V ac adapters
n Fully Compliant 802.3af Power Interface Port
n 80V, 1Ω, 400 mA Internal MOSFET
Block Diagram
DS201684
n Detection Resistor Disconnect Function
n Programmable Classification Current
n Programmable Under-voltage Lockout with
n Thermal Shutdown Protection
n Auxiliary Power Enable Pin
n Current Mode Pulse Width Modulator
n Supports both Isolated and Non-Isolated Applications
n Error Amplifier and Reference for Non-Isolated
n Programmable Oscillator Frequency
n Programmable Soft-start
n 80% Maximum Duty Cycle Limiter, Slope Compensation
n 50% Maximum Duty Cycle Limiter, No Slope
Packages
n TSSOP-16
Programmable Hysteresis
Applications
(-80 device)
Compensation (-50 device)
November 2005
www.national.com
20168401

Related parts for LM5071MT-50

LM5071MT-50 Summary of contents

Page 1

LM5071 Power Over Ethernet PD Controller with Auxiliary Power Interface General Description The LM5071 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 ...

Page 2

... Block Diagram (Continued) Connection Diagram Ordering Information Order Number Description LM5071MT-50 50% Duty Cycle Limit LM5071MTX-50 50% Duty Cycle Limit LM5071MT-80 80% Duty Cycle Limit LM5071MTX-80 80% Duty Cycle Limit www.national.com FIGURE 1. Simplified Block Diagram 20168403 16 Lead TSSOP NSC Package Type / Drawing TSSOP-16/MTC-16 TSSOP-16/MTC-16 ...

Page 3

Pin Descriptions Pin Name Description 1 VIN System high potential input. 2 RSIG Signature resistor pin. 3 RCLASS Classification resistor pin. 4 AUX Auxiliary input power startup pin. 5 UVLO Line under-voltage lockout. 6 UVLORTN Return for the external UVLO ...

Page 4

Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. V ,RTN RSIG AUX UVLO RCLASS ...

Page 5

Electrical Characteristics Specifications in standard type face are for T perature range. Unless otherwise specified: V Symbol Parameter V Supply CC V UVLO (Rising UVLO (Falling) CC Supply Current (Icc) Error Amplifier GBW Gain Bandwidth DC Gain Input ...

Page 6

Electrical Characteristics Specifications in standard type face are for T perature range. Unless otherwise specified: V Symbol Parameter Thermal Shutdown Tsd Thermal Shutdown Temp. Thermal Shutdown Hysteresis Thermal Resistance θ Junction to Ambient JA Note 1: Absolute Maximum Ratings are ...

Page 7

Typical Performance Characteristics Default Current Limit vs Temperature UVLO Hysteresis Current vs Temperature Error Amp Input Voltage vs temperature Oscillator Frequency vs RT Resistance 20168409 Softstart Current vs Temperature 20168408 Oscillator Frequency vs Temperature 20168417 7 20168413 20168415 RT = ...

Page 8

Typical Performance Characteristics UVLO Threshold vs Temperature www.national.com (Continued) Input Current vs Input Voltage 20168412 20168406 8 20168407 ...

Page 9

Specialized Block Diagrams FIGURE 2. Top Level Block Diagram FIGURE 3. PWM Controller Block Diagram 9 20168404 20168405 www.national.com ...

Page 10

Detailed Operating Description The LM5071 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. Major features of the PD interface portion ...

Page 11

Classification (Continued) TABLE 2. Classification Levels and Required External Resistors Class PMIN PMAX ICLASS (MIN) 0 0.44W 12.95W 0mA 1 0.44W 3.84W 9mA 2 3.84W 6.49W 17mA 3 6.49W 12.95W 26mA 4 Reserved Reserved 36mA Undervoltage Lockout (UVLO) The IEEE ...

Page 12

Power Supply Operation Once the UVLO threshold has been satisfied, the interface controller of the LM5071 will charge up the SMPS input capacitor through the internal power MOSFET. This load capacitance provides input filtering for the power converter section and ...

Page 13

Error Amplifier An internal high gain error amplifier is provided within the LM5071. The amplifier’s non-inverting reference is set to a fixed reference voltage of 1.25V. The inverting input is con- nected to the FB pin. In non-isolated applications, the ...

Page 14

Gate Driver and Maximum Duty Cycle Limit (Continued) plished with an internal toggle flip-flop which ensures an accurate duty cycle limit. The internal oscillator frequency of the LM5071-50 is therefore twice the operating frequency of the PWM controller (OUT pin). ...

Page 15

15 www.national.com ...

Page 16

www.national.com 16 ...

Page 17

17 www.national.com ...

Page 18

Physical Dimensions inches (millimeters) unless otherwise noted National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and ...

Related keywords