5071MT Datasheet PDF - National Semiconductor
| Part Number | 5071MT | |
| Description | LM5071MT | |
| Manufacturers | National Semiconductor | |
| Logo |  |
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November 2005
www.DataSheet4U.com
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
n Detection Resistor Disconnect Function
n Programmable Classification Current
n Programmable Under-voltage Lockout with
Programmable Hysteresis
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
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)
Packages
n TSSOP-16
Block Diagram
© 2005 National Semiconductor Corporation DS201684
20168401
www.national.com
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Electrical Characteristics (Note 3) (Continued)
Specifications in standard type face are for TJ= +25˚C and those in boldface type apply over the full operatinwg wjuwnc.DtioantatSehme-et4U.com
perature range. Unless otherwise specified: VIN = 48V, VCC = 10V, RT = 30.3kΩ.
Symbol
Parameter
Conditions
Min Typ Max Units
VCC Supply
VCC UVLO (Rising)
VccReg VccReg –
– 100mV
300mV
VCC UVLO (Falling)
Supply Current (Icc)
Cload = 0
5.9 6.25 6.6 V
1.5 3 mA
Error Amplifier
GBW
Gain Bandwidth
4 MHz
DC Gain
75 dB
Input Voltage
FB = COMP
1.219
1.281
V
1.212
1.288
COMP Sink Capability
FB=1.5V COMP=1V
5 20
mA
Current Limit
ILIM Delay to Output
CS step from 0 to 0.6V, time to
20
ns
onset of OUT transition (90%)
Cycle by Cycle Current Limit
0.44
0.5
0.56
V
Threshold Voltage
Leading Edge Blanking Time
55 ns
CS Sink Impedance (clocked)
25 55 Ω
Softstart
Softstart Current Source
7 10 13 uA
Oscillator(Note 5)
Frequency1
175 200 225 KHz
(RT = 30.3K)
Frequency2
505 580 665 KHz
(RT = 10.5K)
Sync threshold
3.1 3.8 V
PWM Comparator
Delay to Output
COMP set to 2V
25 ns
CS stepped 0 to 0.4V, time to
onset of OUT transition low
Min Duty Cycle
COMP=0V
0%
Max Duty Cycle (-80 Device)
80 %
Max Duty Cycle (-50 Device)
50 %
COMP to PWM Comparator
0.33
Gain
COMP Open Circuit Voltage
4.5 5.4 6.3 V
COMP Short Circuit Current COMP= 0V
0.6 1.1 1.5 mA
Slope Compensation
Slope Comp Amplitude
Delta increase at PWM
105 mV
(LM5071-80 Device Only)
Comparator to CS
Output Section
Output High Saturation
Output Low Saturation
Rise time
Iout = 50mA,
VCC - VOUT
Iout = 100mA
Cload = 1nF
0.25
0.25
15
0.75
0.75
V
V
ns
Fall time
Cload = 1nF
15 ns
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Part DetailsOn this page, you can learn information such as the schematic, equivalent, pinout, replacement, circuit, and manual for 5071MT electronic component. |
| Information | Total 18 Pages | |
| Link URL | [ Copy URL to Clipboard ] | |
| Download | [ 5071MT.PDF Datasheet ] | |
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