3A, 52kHz, Step-Down Switching Regulator
FEATURES
3.3V, 5.0V, 12V and Adjustable Output Versions
Adjustable Version Output Voltage Range, 1.23 to 37V
+/- 4% maximum over line and load conditions
Guaranteed 3.0A Output Current
Wide Input Voltage Range
Requires Only 4 External Components
52kHz Fixed Frequency Internal Oscillator
TTL Shutdown Capability, Low Power Standby Mode
High Efficiency
Uses Readily Available Standard Inductors
Thermal Shutdown and Current Limit Protection
Moisture Sensitivity Level 3 for SMD packages
SOP8-PP PKG
LM2576
TO-220 PKG
TO-263 PKG
APPLICATION
Simple High-Efficiency Step-Down(Buck) Regulator
Efficient Pre-Regulator for Linear Regulators
On-Card Switching Regulators
Positive to Negative Converter(Buck-Boost)
Negative Step-Up Converters
Power Supply for Battery Chargers
ORDERING INFORMATION
Device
LM2576DP-X.X
LM2576T-X.X
LM2576R-X.X
Marking
LM2576-X.X
LM2576-X.X
LM2576-X.X
Package
SOP8-PP
TO-220
TO-263
DESCRIPTION
The LM2576 series of regulators are monolithic integrated circuits ideally suited for easy and convenient
design of a step-down switching regulator (buck converter).
All circuits of this series are capable of driving a 3.0A load with excellent line and load regulation. These
devices are available in fixed output voltages of 3.3V, 5.0V, 12V and an adjustable output version.
These regulators were designed to minimize the number of external components to simplify the power supply
design. Standard series of inductors optimized for use with the LM2576 are offered by several different inductor
manufacturers.
Since the LM2576 converter is a switch-mode power supply, its efficiency is significantly higher in comparison
with popular three-terminal linear regulators, especially with higher input voltages.
In many cases, the power dissipated is so low that no heatsink is required or its size could be reduced
dramatically. A standard series of inductors optimized for use with the LM2576 are available from several
different manufacturers. This feature greatly simplifies the design of switch-mode power supplies. The LM2576
features include a guaranteed +/- 4% tolerance on output voltage within specified input voltages and output
load conditions, and +/-10% on the oscillator frequency (+/- 2% over 0˚C to 125˚C).
External shutdown is included, featuring 80㎂(typical) standby current. The output switch includes cycle-by-
cycle current limiting, as well as thermal shutdown for full protection under fault conditions.
Aug. 2015 – Rev. 1.6
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HTC
3A, 52kHz, Step-Down Switching Regulator
Ordering Information
V
OUT
Package
SOP8-PP
ADJ
TO220-5L
TO263-5L
SOP8-PP
3.3V
TO220-5L
TO263-5L
SOP8-PP
5.0V
TO220-5L
TO263-5L
SOP8-PP
12V
TO220-5L
TO263-5L
Order No.
LM2576DP-ADJ
LM2576T-ADJ
LM2576R-ADJ
LM2576DP-3.3
LM2576T-3.3
LM2576R-3.3
LM2576DP-5.0
LM2576T-5.0
LM2576R-5.0
LM2576DP-12
LM2576T-12
LM2576R-12
Description
3A, Adjustable, 52kHz, On/off
3A, Adjustable, 52kHz, On/off
3A, Adjustable, 52kHz, On/off
3A, Fixed, 52kHz, On/off
3A, Fixed, 52kHz, On/off
3A, Fixed, 52kHz, On/off
3A, Fixed, 52kHz, On/off
3A, Fixed, 52kHz, On/off
3A, Fixed, 52kHz, On/off
3A, Fixed, 52kHz, On/off
3A, Fixed, 52kHz, On/off
3A, Fixed, 52kHz, On/off
Package Marking
LM2576-ADJ
LM2576-ADJ
LM2576-ADJ
LM2576-3.3
LM2576-3.3
LM2576-3.3
LM2576-5.0
LM2576-5.0
LM2576-5.0
LM2576-12
LM2576-12
LM2576-12
LM2576
Status
Active
Active
Active
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Active
Active
Active
Active
Active
Contact Us
Active
Active
LM
2576
Output Voltage : ADJ / 3.3V / 5.0V /12V
Package Type
DP : SOP8-PP
T : TO220-5L
R : TO263-5L
Root Name
Product Code
Aug. 2015 – Rev. 1.6
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3A, 52kHz, Step-Down Switching Regulator
PIN CONFIGURATION
ON/OFF
VIN 1
VOUT 2
FEEDBACK 3
ON/OFF
4
Exposed
PAD
LM2576
8 N.C
7 N.C
6 GND
5 N.C.
FEEDBACK
GND
VOUT
VIN
ON/OFF
FEEDBACK
GND
VOUT
VIN
SOP8-PP
TO220-5L
TO263-5L
PIN DESCRIPTION
Package
TO-220 5L
SOP8-PP
TO-263 5L
This pin is the positive input supply for the LM2576 step–down
switching regulator.
In order to minimize voltage transients and to supply the switching
currents needed by the regulator, a suitable input bypass capacitor
must be present. (Cin in Figure 1).
This is the emitter of the internal switch. The saturation voltage
V
SAT
of this output switch is typically 1.5V. It should be kept in mind
that the PCB area connected to this pin should be kept to a
minimum in order to minimize coupling to sensitive circuitry.
Circuit ground pin. See the information about the printed circuit
board layout.
This pin senses regulated output voltage to complete the feedback
loop.
The signal is divided by the internal resistor divider network R2, R1
and applied to the non–inverting input of the internal error amplifier.
In the adjustable version of the LM2576 switching regulator this pin
is the direct input of the error amplifier and the resistor network R2,
R1 is connected externally to allow programming of the output
voltage.
It allows the switching regulator circuit to be shutdown using logic
level signals, thus dropping the total input supply current to
approximately 80uA.
The threshold voltage is typically 1.4V. Applying a voltage above
this value (up to +Vin) shuts the regulator off. If the voltage applied
to this pin is lower than 1.4V or if this pin is left open, the regulator
will be in the "on" condition
No Connect.
Symbol
Description
1
1
VIN
2
2
VOUT
3
6
GND
4
3
FEEDBACK
5
4
ON/OFF
-
5, 7, 8
N.C.
* Exposed Pad of SOP8-PP package should be externally connected to GND.
Aug. 2015 – Rev. 1.6
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HTC
3A, 52kHz, Step-Down Switching Regulator
Typical Application (Fixed Output Voltage Versions)
Figure 1. Block Diagram and Typical Application
LM2576
Aug. 2015 – Rev. 1.6
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HTC
3A, 52kHz, Step-Down Switching Regulator
ABSOLUTE MAXIMUM RATINGS
LM2576
(Absolute Maximum Ratings indicate limits beyond which damage to the device may occur)
Rating
Maximum Supply Voltage
On/Off Pin Input Voltage
Output Voltage to Ground (Steady-State)
Power Dissipation
SOP8-PP 8Lead
Thermal Resistance, Junction to Ambient
Thermal Resistance, Junction to Case
TO-220 5Lead
Thermal Resistance, Junction to Ambient
Thermal Resistance, Junction to Case
TO-263 5Lead
Thermal Resistance, Junction to Ambient
Thermal Resistance, Junction to Case
Storage Temperature Range
Minimum ESD Rating(Human Body Model:
C=100 pF, R=1.5kΩ
Lead Temperature (Soldering, 10seconds)
Maximum Junction Temperature
Symbol
Vin
-
-
P
D
θ
JA
θ
JC
P
D
θ
JA
θ
JC
P
D
θ
JA
θ
JC
T
STG
-
-
T
J
Value
45
-0.3V
≤
V
≤
+Vin
-1.0
Internally Limited
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Contact us
Internally Limited
65
5
Internally Limited
70
5
-60 to +150
2.0
260
150
UNIT
V
V
V
W
℃/W
℃/W
W
℃/W
℃/W
W
℃/W
℃/W
℃
kV
℃
℃
OPERATING RATINGS
(Operating Ratings indicate conditions for which the device is intended to be
functional, but do not guarantee specific performance limits. For guaranteed specifications, see the
Electrical Characteristics.)
Rating
Operating Junction Temperature Range
Supply Voltage
Symbol
T
J
Vin
Value.
-40 to +125
40
Unit
℃
V
Aug. 2015 – Rev. 1.6
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HTC
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