NSC LM2576T-15, LM2576T-3.3, LM2576T-5.0, LM2576HVT-ADJ, LM2576HVT-5.0 Datasheet

LM2576/LM2576HV Series
SIMPLE SWITCHER

®

3A Step-Down Voltage Regulator

LM2576/LM2576HV Series SIMPLE SWITCHER 3A Step-Down Voltage Regulator

June 1999

General Description

The LM2576 series of regulators are monolithic integrated
circuits that provide all the active functions for a step-down
(buck) switching regulator, capable of driving 3A load with
excellent line and load regulation. These devices are avail­able in fixed output voltages of 3.3V, 5V, 12V, 15V, and an
adjustable output version.

Requiring aminimumnumber of external components, these
regulators are simple to use and include internal frequency
compensation and a fixed-frequency oscillator.

The LM2576 series offers a high-efficiency replacement for
popular three-terminal linear regulators. It substantially re­duces the size of the heat sink, and in some cases no heat
sink is required.

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.

Other features include a guaranteed
put voltage within specified input voltages and output load
conditions, and
shutdown is included, featuring 50 µA (typical) standby cur­rent. The output switch includes cycle-by-cycle current limit­ing, as well as thermal shutdown for full protection under
fault conditions.

±

10%on the oscillator frequency. External

±

4%tolerance on out-

Features

n 3.3V, 5V, 12V, 15V, and adjustable output versions
n Adjustable version output voltage range,

n Guaranteed 3A output current
n Wide input voltage range, 40V up to 60V for

n Requires only 4 external components
n 52 kHz fixed frequency internal oscillator
n TTL shutdown capability, low power standby mode
n High efficiency
n Uses readily available standard inductors
n Thermal shutdown and current limit protection
n P+ Product Enhancement tested

Applications

n Simple high-efficiency step-down (buck) regulator
n Efficient pre-regulator for linear regulators
n On-card switching regulators
n Positive to negative converter (Buck-Boost)

Typical Application (Fixed Output Voltage Versions)

1.23V to 37V (57V for HV version)
line and load conditions

HV version

±

4%max over

DS011476-1

FIGURE 1.

SIMPLE SWITCHER®is a registered trademark of National Semiconductor Corporation.

© 1999 National Semiconductor Corporation DS011476 www.national.com

Block Diagram

3.3V R2=1.7k
5V, R2=3.1k
12V, R2=8.84k
15V, R2=11.3k
For ADJ. Version
R1=Open, R2=0Ω
Patent Pending

Ordering Information

Temperature

Range

−40˚C ≤ T
≤ 125˚C

A

3.3 5.0 12 15 ADJ Number

LM2576HVS-3.3 LM2576HVS-5.0 LM2576HVS-12 LM2576HVS-15 LM2576HVS-ADJ TS5B TO-263
LM2576S-3.3 LM2576S-5.0 LM2576S-12 LM2576S-15 LM2576S-ADJ
LM2576HVSX-3.3 LM2576HVSX-5.0 LM2576HVSX-12 LM2576HVSX-15 LM2576HVSX-ADJ TS5B
LM2576SX-3.3 LM2576SX-5.0 LM2576SX-12 LM2576SX-15 LM2576SX-ADJ
LM2576HVT-3.3 LM2576HVT-5.0 LM2576HVT-12 LM2576HVT-15 LM2576HVT-ADJ T05A TO-220
LM2576T-3.3 LM2576T-5.0 LM2576T-12 LM2576T-15 LM2576T-ADJ
LM2576HVT-3.3 LM2576HVT-5.0 LM2576HVT-12 LM2576HVT-15 LM2576HVT-ADJ T05D
Flow LB03 Flow LB03 Flow LB03 Flow LB03 Flow LB03
LM2576T-3.3 LM2576T-5.0 LM2576T-12 LM2576T-15 LM2576T-ADJ
Flow LB03 Flow LB03 Flow LB03 Flow LB03 Flow LB03

DS011476-2

Output Voltage NS Package Package

Type

Tape & Reel

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Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

Maximum Supply Voltage

LM2576 45V

LM2576HV 63V
ON /OFF Pin Input Voltage
Output Voltage to Ground

(Steady State) −1V
Power Dissipation Internally Limited

−0.3V ≤ V ≤ +V

Minimum ESD Rating

(C=100 pF, R=1.5 kΩ)2kV

Lead Temperature

(Soldering, 10 Seconds) 260˚C

Operating Ratings

Temperature Range

IN

LM2576/LM2576HV −40˚C ≤ T

Supply Voltage

LM2576 40V
LM2576HV 60V

≤ +125˚C

J

Storage Temperature Range −65˚C to +150˚C
Maximum Junction Temperature 150˚C

LM2576-3.3, LM2576HV-3.3
Electrical Characteristics

Specifications with standard type face are for T
Range.

Symbol Parameter Conditions LM2576-3.3 Units

SYSTEM PARAMETERS (Note 3) Test Circuit

V

OUT

Output Voltage V

Circuit of

V

OUT

Output Voltage 6V ≤ VIN≤ 40V, 0.5A ≤ I
LM2576 Circuit of

V

OUT

Output Voltage 6V ≤ VIN≤ 60V, 0.5A ≤ I
LM2576HV Circuit of

η Efficiency V

=

25˚C, and those with boldface type apply over full Operating Temperature

J

LM2576HV-3.3

(Limits)

Typ Limit

(Note 2)

Figure 2

=

12V, I

IN

LOAD

Figure 2

=

0.5A 3.3 V

3.234 V(Min)

3.366 V(Max)

≤ 3A 3.3 V

Figure 2

LOAD

3.168/3.135 V(Min)

3.432/3.465 V(Max)

≤ 3A 3.3 V

Figure 2

LOAD

3.168/3.135 V(Min)

3.450/3.482 V(Max)

=

12V, I

IN

=

3A 75

LOAD

%

LM2576-5.0, LM2576HV-5.0
Electrical Characteristics

Specifications with standard type face are for T
Temperature Range.

Symbol Parameter Conditions LM2576-5.0 Units

SYSTEM PARAMETERS (Note 3) Test Circuit

V

OUT

V

OUT

Output Voltage V

Output Voltage 0.5A ≤ I
LM2576 8V ≤ V

V

OUT

Output Voltage 0.5A ≤ I
LM2576HV 8V ≤ V

η Efficiency V

=

25˚C, and those with

J

Figure 2

boldface type apply over full Operating

LM2576HV-5.0

Typ Limit

(Note 2)

Figure 2

=

12V, I

IN

Circuit of

LOAD

Figure 2

=

0.5A 5.0 V

4.900 V(Min)

5.100 V(Max)

≤ 3A, 5.0 V

LOAD

≤ 40V 4.800/4.750 V(Min)

IN

Circuit of

Figure 2

≤ 3A, 5.0 V

LOAD

≤ 60V 4.800/4.750 V(Min)

IN

Circuit of

Figure 2

=

12V, I

IN

=

3A 77

LOAD

5.200/5.250 V(Max)

5.225/5.275 V(Max)

(Limits)

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%

LM2576-12, LM2576HV-12
Electrical Characteristics

Specifications with standard type face are for T
Range.

Symbol Parameter Conditions LM2576-12 Units

SYSTEM PARAMETERS (Note 3) Test Circuit

V

OUT

V

OUT

Output Voltage V

Output Voltage 0.5A ≤ I
LM2576 15V ≤ V

V

OUT

Output Voltage 0.5A ≤ I
LM2576HV 15V ≤ V

η Efficiency V

=

25˚C, and those with boldface type apply over full Operating Temperature

J

LM2576HV-12

Typ Limit

(Note 2)

Figure 2

=

25V, I

IN

Circuit of

LOAD

Figure 2

=

0.5A 12 V

11.76 V(Min)

12.24 V(Max)

≤ 3A, 12 V

LOAD

≤ 40V 11.52/11.40 V(Min)

IN

Circuit of

Circuit of

Figure 2

≤ 3A, 12 V

LOAD

≤ 60V 11.52/11.40 V(Min)

IN

Figure 2

=

15V, I

IN

=

3A 88

LOAD

12.48/12.60 V(Max)

12.54/12.66 V(Max)

(Limits)

LM2576-15, LM2576HV-15
Electrical Characteristics

Specifications with standard type face are for T
Range.

Symbol Parameter Conditions LM2576-15 Units

SYSTEM PARAMETERS (Note 3) Test Circuit

V

OUT

V

OUT

Output Voltage V

Output Voltage 0.5A ≤ I
LM2576 18V ≤ V

V

OUT

Output Voltage 0.5A ≤ I
LM2576HV 18V ≤ V

η Efficiency V

=

25˚C, and those with boldface type apply over full Operating Temperature

J

LM2576HV-15

Typ Limit

(Note 2)

Figure 2

=

25V, I

IN

Circuit of

LOAD

Figure 2

=

0.5A 15 V

14.70 V(Min)

15.30 V(Max)

≤ 3A, 15 V

LOAD

≤ 40V 14.40/14.25 V(Min)

IN

Circuit of

Circuit of

Figure 2

≤ 3A, 15 V

LOAD

≤ 60V 14.40/14.25 V(Min)

IN

Figure 2

=

18V, I

IN

=

3A 88

LOAD

15.60/15.75 V(Max)

15.68/15.83 V(Max)

(Limits)

%

%

LM2576-ADJ, LM2576HV-ADJ
Electrical Characteristics

Specifications with standard type face are for T
Range.

Symbol Parameter Conditions LM2576-ADJ Units

SYSTEM PARAMETERS (Note 3) Test Circuit

V

OUT

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Feedback Voltage V

=

25˚C, and those with boldface type apply over full Operating Temperature

J

LM2576HV-ADJ

Typ Limit

(Note 2)

Figure 2

=

12V, I

IN

=

V

OUT

Circuit of

=

0.5A 1.230 V

LOAD

5V, 1.217 V(Min)

Figure 2

1.243 V(Max)

(Limits)

LM2576-ADJ, LM2576HV-ADJ
Electrical Characteristics

Specifications with standard type face are for T
Range.

Symbol Parameter Conditions LM2576-ADJ Units

SYSTEM PARAMETERS (Note 3) Test Circuit

V

OUT

V

OUT

η Efficiency V

Feedback Voltage 0.5A ≤ I
LM2576 8V ≤ V

Feedback Voltage 0.5A ≤ I
LM2576HV 8V ≤ V

(Continued)

=

25˚C, and those with boldface type apply over full Operating Temperature

J

LM2576HV-ADJ

Typ Limit

(Note 2)

Figure 2

≤ 3A, 1.230 V

LOAD

≤ 40V 1.193/1.180 V(Min)

IN

=

V

5V, Circuit of

OUT

LOAD

≤ 60V 1.193/1.180 V(Min)

IN

=

V

5V, Circuit of

OUT

=

12V, I

IN

LOAD

Figure 2

1.267/1.280 V(Max)

≤ 3A, 1.230 V

=

Figure 2

3A, V

=

5V 77

OUT

1.273/1.286 V(Max)

(Limits)

%

All Output Voltage Versions
Electrical Characteristics

Specifications with standard type face are for T
Range. Unless otherwise specified, V

=

30V for the 15V version. I

V

IN

LOAD

IN

=

Symbol Parameter Conditions LM2576-XX Units

DEVICE PARAMETERS

I

b

f

O

V

SAT

Feedback Bias Current V
Oscillator Frequency (Note 11) 52 kHz

Saturation Voltage I

DC Max Duty Cycle (ON) (Note 5) 98

I

I

I

I

CL

L

Q

STBY

Current Limit (Notes 4, 11) 5.8 A

Output Leakage Current (Notes 6, 7): Output=0V 2 mA(Max)

Quiescent Current (Note 6) 5 mA

Standby Quiescent ON /OFF Pin=5V (OFF) 50 µA
Current 200 µA(Max)

θ

JA

θ

JA

θ

JC

θ

JA

Thermal Resistance T Package, Junction to Ambient (Note 8) 65

=

25˚C, and those with boldface type apply over full Operating Temperature

J

=

12V for the 3.3V, 5V, and Adjustable version, V

500 mA.

=

25V for the 12V version, and

IN

LM2576HV-XX

Typ Limit

(Note 2)

=

5V (Adjustable Version Only) 50 100/500 nA

OUT

47/42 kHz

58/63 kHz

=

3A (Note 4) 1.4 V

OUT

1.8/2.0 V(Max)

93

4.2/3.5 A(Min)

6.9/7.5 A(Max)

Output=−1V 7.5 mA
Output=−1V 30 mA(Max)

10 mA(Max)

T Package, Junction to Ambient (Note 9) 45 ˚C/W
T Package, Junction to Case 2
S Package, Junction to Ambient (Note 10) 50

(Limits)

(Min)

(Max)

%

%

(Min)

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All Output Voltage Versions
Electrical Characteristics

Specifications with standard type face are for T
Range. Unless otherwise specified, V

=

30V for the 15V version. I

V

IN

Symbol Parameter Conditions LM2576-XX Units

ON /OFF CONTROL Test Circuit

V

IH

V

IL

I

IH

ON /OFF Pin V
Logic Input Level V
ON /OFF Pin Input ON /OFF Pin=5V (OFF) 12 µA
Current 30 µA(Max)

I

IL

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.Operating Ratings indicate conditions for which the device is in­tended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.

Note 2: All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). All room temperature limits are 100%produc-
tion tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.

Note 3: External components such as the catch diode, inductor,input and output capacitors can affect switching regulator system performance. When the LM2576/
LM2576HV is used as shown in the

Note 4: Output pin sourcing current. No diode, inductor or capacitor connected to output.
Note 5: Feedback pin removed from output and connected to 0V.
Note 6: Feedback pin removed from output and connected to +12V for the Adjustable, 3.3V, and 5V versions, and +25V for the 12V and 15V versions, to force the

output transistor OFF.

Note 7: V
Note 8: Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically, with

board with minimum copper area.
Note 9: Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically,with

containing approximately 4 square inches of copper area surrounding the leads.
Note 10: If the TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper area thermally connected to the package. Using

0.5 square inches of copper area, θ
Note 11: The oscillator frequency reduces to approximately 11kHz in the event of an output short or an overload which causes the regulated output voltage to drop

approximately 40%from the nominal output voltage. This self protection feature lowers the average power dissipation of the IC by lowering the minimum duty cycle
from 5%down to approximately 2%.

=

40V (60V for high voltage version).

IN

LOAD

Figure 2

Figure 2

is 50˚C/W, with 1 square inch of copper area, θJAis 37˚C/W, and with 1.6 or more square inches of copper area, θJAis 32˚C/W.

JA

(Continued)

=

25˚C, and those with boldface type apply over full Operating Temperature

J

=

12V for the 3.3V, 5V, and Adjustable version, V

IN

=

500 mA.

=

25V for the 12V version, and

IN

LM2576HV-XX

(Limits)

Typ Limit

(Note 2)

=

0V 1.4 2.2/2.4 V(Min)

OUT

=

Nominal Output Voltage 1.2 1.0/0.8 V(Max)

OUT

ON /OFF Pin=0V (ON) 0µA

10 µA(Max)

test circuit, system performance will be as shown in system parameters section of Electrical Characteristics.

1

⁄2inch leads in a socket, or on a PC

1

⁄4inch leads soldered to a PC board

Typical Performance Characteristics (Circuit of

Normalized Output Voltage

DS011476-27

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Line Regulation

Figure 2

DS011476-28

)

Dropout Voltage

DS011476-29

Typical Performance Characteristics (Circuit of

Figure 2

) (Continued)

Current Limit

Oscillator Frequency

Minimum Operating Voltage

DS011476-30

DS011476-33

Quiescent Current

Switch Saturation
Voltage

Quiescent Current
vs Duty Cycle

DS011476-31

DS011476-34

Standby
Quiescent Current

DS011476-32

Efficiency

DS011476-35

Feedback Voltage
vs Duty Cycle

DS011476-36

DS011476-37

DS011476-38

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