National Semiconductor LM1575, LM2575, LM2575HV Technical data

April 2007

LM1575/LM2575/LM2575HV
SIMPLE SWITCHER® 1A Step-Down Voltage Regulator

LM1575/LM2575/LM2575HV Series SIMPLE SWITCHER 1A Step-Down Voltage Regulator

General Description

The LM2575 series of regulators are monolithic integrated
circuits that provide all the active functions for a step-down
(buck) switching regulator, capable of driving a 1A 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 a minimum number of external components, these
regulators are simple to use and include internal frequency
compensation and a fixed-frequency oscillator.

The LM2575 series offers a high-efficiency replacement for
popular three-terminal linear regulators. It substantially re­duces the size of the heat sink, and in many cases no heat
sink is required.

A standard series of inductors optimized for use with the
LM2575 are available from several different manufacturers.
This feature greatly simplifies the design of switch-mode pow­er supplies.

Other features include a guaranteed ±4% tolerance on output
voltage within specified input voltages and output load con­ditions, and ±10% on the oscillator frequency. External 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.

Typical Application

(Fixed Output Voltage Versions)

Features

3.3V, 5V, 12V, 15V, and adjustable output versions

■

Adjustable version output voltage range,

■

1.23V to 37V (57V for HV version) ±4% max over
line and load conditions

Guaranteed 1A output current

■

Wide input voltage range, 40V up to 60V for HV version

■

Requires only 4 external components

■

52 kHz fixed frequency internal oscillator

■

TTL shutdown capability, low power standby mode

■

High efficiency

■

Uses readily available standard inductors

■

Thermal shutdown and current limit protection

■

P+ Product Enhancement tested

■

Applications

Simple high-efficiency step-down (buck) regulator

■

Efficient pre-regulator for linear regulators

■

On-card switching regulators

■

Positive to negative converter (Buck-Boost)

■

Note: Pin numbers are for the TO-220 package.

SIMPLE SWITCHER® is a registered trademark of National Semiconductor Corporation

© 2007 National Semiconductor Corporation 11475 www.national.com

1147501

Block Diagram and Typical Application

LM1575/LM2575/LM2575HV

3.3V, R2 = 1.7k

5V, R2 = 3.1k

12V, R2 = 8.84k

15V, R2 = 11.3k

For ADJ. Version
R1 = Open, R2 = 0Ω

Note: Pin numbers are for the TO-220 package.

1147502

FIGURE 1.

www.national.com 2

Connection Diagrams

(XX indicates output voltage option. See Ordering Information table for complete part number.)

LM1575/LM2575/LM2575HV

Straight Leads

5–Lead TO-220 (T)

Top View

LM2575T-XX or LM2575HVT-XX

See NS Package Number T05A

16–Lead DIP (N or J)

*No Internal Connection

LM2575N-XX or LM2575HVN-XX

See NS Package Number N16A

LM1575J-XX-QML

See NS Package Number J16A

1147522

Top View

Bent, Staggered Leads

5-Lead TO-220 (T)

Top View

1147525

1147523

*No Internal Connection

LM2575M-XX or LM2575HVM-XX

See NS Package Number M24B

LM2575T-XX Flow LB03 or

Side View

LM2575HVT-XX Flow LB03

See NS Package Number T05D

24-Lead Surface Mount (M)

1147526

Top View

1147524

5-Lead Surface-Mount Package

TO-263(S)

Top View

Side View

1147530

1147529

LM2575S-XX or LM2575HVS-XX
See NS Package Number TS5B

3 www.national.com

Ordering Information

Package NSC Standard High Temperature

Type Package Voltage Rating Voltage Rating Range

Number (40V) (60V)

5-Lead TO-220 T05A LM2575T-3.3 LM2575HVT-3.3

Straight Leads LM2575T-5.0 LM2575HVT-5.0

LM2575T-12 LM2575HVT-12

LM2575T-15 LM2575HVT-15

LM2575T-ADJ LM2575HVT-ADJ

5-Lead TO-220 T05D LM2575T-3.3 Flow LB03 LM2575HVT-3.3 Flow LB03

LM1575/LM2575/LM2575HV

Bent and LM2575T-5.0 Flow LB03 LM2575HVT-5.0 Flow LB03

Staggered Leads LM2575T-12 Flow LB03 LM2575HVT-12 Flow LB03

LM2575T-15 Flow LB03 LM2575HVT-15 Flow LB03

LM2575T-ADJ Flow LB03 LM2575HVT-ADJ Flow LB03

16-Pin Molded N16A LM2575N-5.0 LM2575HVN-5.0

DIP LM2575N-12 LM2575HVN-12

LM2575N-15 LM2575HVN-15

LM2575N-ADJ LM2575HVN-ADJ

24-Pin M24B LM2575M-5.0 LM2575HVM-5.0

Surface Mount LM2575M-12 LM2575HVM-12

LM2575M-15 LM2575HVM-15

LM2575M-ADJ LM2575HVM-ADJ

5-Lead TO-263 TS5B LM2575S-3.3 LM2575HVS-3.3

Surface Mount LM2575S-5.0 LM2575HVS-5.0

LM2575S-12 LM2575HVS-12

LM2575S-15 LM2575HVS-15

LM2575S-ADJ LM2575HVS-ADJ

16-Pin Ceramic J16A LM1575J-3.3-QML

DIP LM1575J-5.0-QML

LM1575J-12-QML

LM1575J-15-QML

LM1575J-ADJ-QML

−40°C ≤ TJ ≤ +125°C

−55°C ≤ TJ ≤ +150°C

www.national.com 4

LM1575/LM2575/LM2575HV

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
LM1575/LM2575 45V
LM2575HV 63V
ON /OFF Pin Input Voltage

Output Voltage to Ground
(Steady State) −1V
Power Dissipation Internally Limited
Storage Temperature Range −65°C to +150°C
Maximum Junction Temperature 150°C

−0.3V ≤ V ≤ +V

IN

Minimum ESD Rating

(C = 100 pF, R = 1.5 kΩ) 2 kV
Lead Temperature
(Soldering, 10 sec.) 260°C

Operating Ratings

Temperature Range
LM1575

LM2575/LM2575HV

Supply Voltage
LM1575/LM2575 40V
LM2575HV 60V

−55°C ≤ TJ ≤ +150°C

−40°C ≤ TJ ≤ +125°C

LM1575-3.3, LM2575-3.3, LM2575HV-3.3 Electrical Characteristics

Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature
Range .

Symbol Parameter Conditions Typ LM1575-3.3 LM2575-3.3 Units

LM2575HV-3.3

Limit Limit

(Note 2) (Note 3)

SYSTEM PARAMETERS (Note 4) Test Circuit Figure 2

V

OUT

V

OUT

V

OUT

η

Output Voltage VIN = 12V, I

Circuit of Figure 2 3.267 3.234 V(Min)

3.333 3.366 V(Max)

Output Voltage

LM1575/LM2575 Circuit of Figure 2 3.200/3.168 3.168/3.135 V(Min)

3.400/3.432 3.432/3.465 V(Max)

Output Voltage

LM2575HV Circuit of Figure 2 3.200/3.168 3.168/3.135 V(Min)

3.416/3.450 3.450/3.482 V(Max)

Efficiency VIN = 12V, I

4.75V ≤ VIN ≤ 40V, 0.2A ≤ I

4.75V ≤ VIN ≤ 60V, 0.2A ≤ I

= 0.2A 3.3 V

LOAD

≤ 1A

LOAD

≤ 1A

LOAD

= 1A 75 %

LOAD

3.3 V

3.3 V

(Limits)

LM1575-5.0, LM2575-5.0, LM2575HV-5.0 Electrical Characteristics

Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature
Range.

Symbol Parameter Conditions Typ LM1575-5.0 LM2575-5.0 Units

LM2575HV-5.0

Limit Limit

(Note 2) (Note 3)

SYSTEM PARAMETERS (Note 4) Test Circuit Figure 2

V

OUT

V

OUT

Output Voltage VIN = 12V, I

Circuit of Figure 2 4.950 4.900 V(Min)

5.050 5.100 V(Max)

Output Voltage

LM1575/LM2575

Circuit of Figure 2 5.150/5.200 5.200/5.250 V(Max)

0.2A ≤ I
8V ≤ VIN ≤ 40V

= 0.2A 5.0 V

LOAD

LOAD

≤ 1A,

5.0 V

4.850/4.800 4.800/4.750 V(Min)

5 www.national.com

(Limits)

Symbol Parameter Conditions Typ LM1575-5.0 LM2575-5.0 Units

LM2575HV-5.0

Limit Limit

(Note 2) (Note 3)

V

OUT

Output Voltage

LM2575HV

0.2A ≤ I

LOAD

≤ 1A,

8V ≤ VIN ≤ 60V

5.0 V

4.850/4.800 4.800/4.750 V(Min)

Circuit of Figure 2 5.175/5.225 5.225/5.275 V(Max)

η

LM1575/LM2575/LM2575HV

LM1575-12, LM2575-12, LM2575HV-12

Efficiency VIN = 12V, I

= 1A 77 %

LOAD

Electrical Characteristics

Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature
Range .

Symbol Parameter Conditions Typ LM1575-12 LM2575-12 Units

LM2575HV-12

Limit Limit

(Note 2) (Note 3)

SYSTEM PARAMETERS (Note 4) Test Circuit Figure 2

V

OUT

V

OUT

V

OUT

η

Output Voltage VIN = 25V, I

= 0.2A 12 V

LOAD

Circuit of Figure 2 11.88 11.76 V(Min)

12.12 12.24 V(Max)

Output Voltage

LM1575/LM2575

0.2A ≤ I

LOAD

≤ 1A,

15V ≤ VIN ≤ 40V

12 V

11.64/11.52 11.52/11.40 V(Min)

Circuit of Figure 2 12.36/12.48 12.48/12.60 V(Max)

Output Voltage

LM2575HV

0.2A ≤ I

LOAD

≤ 1A,

15V ≤ VIN ≤ 60V

12 V

11.64/11.52 11.52/11.40 V(Min)

Circuit of Figure 2 12.42/12.54 12.54/12.66 V(Max)

Efficiency VIN = 15V, I

= 1A 88 %

LOAD

(Limits)

(Limits)

LM1575-15, LM2575-15, LM2575HV-15 Electrical Characteristics

Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature
Range .

Symbol Parameter Conditions Typ LM1575-15 LM2575-15 Units

LM2575HV-15

Limit Limit

(Note 2) (Note 3)

SYSTEM PARAMETERS (Note 4) Test Circuit Figure 2

V

OUT

Output Voltage VIN = 30V, I

= 0.2A 15 V

LOAD

Circuit of Figure 2 14.85 14.70 V(Min)

15.15 15.30 V(Max)

V

OUT

Output Voltage

LM1575/LM2575

0.2A ≤ I

LOAD

≤ 1A,

18V ≤ VIN ≤ 40V

15 V

14.55/14.40 14.40/14.25 V(Min)

Circuit of Figure 2 15.45/15.60 15.60/15.75 V(Max)

V

OUT

Output Voltage

LM2575HV

0.2A ≤ I

LOAD

≤ 1A,

18V ≤ VIN ≤ 60V

15 V

14.55/14.40 14.40/14.25 V(Min)

Circuit of Figure 2 15.525/15.675 15.68/15.83 V(Max)

η

Efficiency VIN = 18V, I

= 1A 88 %

LOAD

(Limits)

www.national.com 6

LM1575-ADJ, LM2575-ADJ, LM2575HV-ADJ Electrical Characteristics

Specifications with standard type face are for TJ= 25°C, and those with boldface type apply over full Operating Temperature
Range.

Symbol Parameter Conditions Typ LM1575-ADJ LM2575-ADJ Units

LM2575HV-ADJ

(Limits)

Limit Limit

(Note 2) (Note 3)

SYSTEM PARAMETERS (Note 4) Test Circuit Figure 2

V

OUT

Feedback Voltage VIN = 12V, I

V

= 0.2A 1.230 V

LOAD

= 5V 1.217 1.217 V(Min)

OUT

Circuit of Figure 2 1.243 1.243 V(Max)

V

OUT

V

OUT

η

Feedback Voltage

LM1575/LM2575

V

Feedback Voltage

LM2575HV

V

Efficiency VIN = 12V, I

0.2A ≤ I

LOAD

≤ 1A,

8V ≤ VIN ≤ 40V

= 5V, Circuit of Figure 2 1.255/1.267 1.267/1.280 V(Max)

OUT

0.2A ≤ I

LOAD

≤ 1A,

8V ≤ VIN ≤ 60V

= 5V, Circuit of Figure 2 1.261/1.273 1.273/1.286 V(Max)

OUT

LOAD

= 1A, V

= 5V 77 %

OUT

1.230 V

1.205/1.193 1.193/1.180 V(Min)

1.230 V

1.205/1.193 1.193/1.180 V(Min)

All Output Voltage Versions Electrical Characteristics

Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature
Range. Unless otherwise specified, VIN = 12V for the 3.3V, 5V, and Adjustable version, VIN = 25V for the 12V version, and VIN =

30V for the 15V version. I

Symbol Parameter Conditions Typ LM1575-XX LM2575-XX Units

DEVICE PARAMETERS

I

b

f

O

Feedback Bias Current V

Oscillator Frequency (Note 13) 52 kHz

47/43 47/42 kHz(Min)

58/62 58/63 kHz(Max)

V

SAT

Saturation Voltage I

1.2/1.4 1.2/1.4 V(Max)

DC Max Duty Cycle (ON) (Note 6) 98 %

93 93 %(Min)

I

CL

Current Limit Peak Current (Notes 5, 13) 2.2 A

1.7/1.3 1.7/1.3 A(Min)

3.0/3.2 3.0/3.2 A(Max)

I

L

Output Leakage

Current

I

Q

Quiescent Current (Note 7) 5 mA

10/12 10 mA(Max)

I

STBY

Standby Quiescent ON /OFF Pin = 5V (OFF) 50

Current 200/500 200

LOAD

= 200 mA.

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

OUT

= 1A (Note 5) 0.9 V

OUT

(Notes 7, 8)  Output = 0V

Output = −1V
          Output = −1V

LM2575HV-XX

(Limits)

Limit Limit

(Note 2) (Note 3)

2 2 mA(Max)

7.5 mA

30 30 mA(Max)

μA

μA(Max)

LM1575/LM2575/LM2575HV

7 www.national.com

Symbol Parameter Conditions Typ LM1575-XX LM2575-XX Units

LM2575HV-XX

Limit Limit

(Note 2) (Note 3)

θ

JA

θ

JA

θ

JC

θ

JA

θ

JA

LM1575/LM2575/LM2575HV

θ

JA

Thermal Resistance T Package, Junction to Ambient (Note 9) 65

T Package, Junction to Ambient (Note 10) 45 °C/W

T Package, Junction to Case 2

N Package, Junction to Ambient (Note 11) 85

M Package, Junction to Ambient (Note 11) 100

S Package, Junction to Ambient (Note 12) 37

ON /OFF CONTROL Test Circuit Figure 2

V

IH

V

IL

I

IH

ON /OFF Pin Logic V

Input Level

= 0V 1.4 2.2/2.4 2.2/2.4 V(Min)

OUT

V

= Nominal Output Voltage 1.2 1.0/0.8 1.0/0.8 V(Max)

OUT

ON /OFF Pin Input ON /OFF Pin = 5V (OFF) 12

Current 30 30

I

IL

ON /OFF Pin = 0V (ON) 0

10 10

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 limits are used to calculate Average
Outgoing Quality Level, and all are 100% production tested.

Note 3: All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). All room temperature limits are 100%
production tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.

Note 4: External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM1575/
LM2575 is used as shown in the Figure 2 test circuit, system performance will be as shown in system parameters section of Electrical Characteristics.

Note 5: Output (pin 2) sourcing current. No diode, inductor or capacitor connected to output pin.

Note 6: Feedback (pin 4) removed from output and connected to 0V.

Note 7: Feedback (pin 4) 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 8: VIN = 40V (60V for the high voltage version).

Note 9: Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically, with ½ inch leads in a socket, or on a

PC board with minimum copper area.

Note 10: Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically, with ½ inch leads soldered to a PC
board containing approximately 4 square inches of copper area surrounding the leads.

Note 11: Junction to ambient thermal resistance with approximately 1 square inch of pc board copper surrounding the leads. Additional copper area will lower
thermal resistance further. See thermal model in Switchers made Simple software.

Note 12: 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, θJA is 50°C/W; with 1 square inch of copper area, θJA is 37°C/W; and with 1.6 or more square inches of copper area,

θJA is 32°C/W.

Note 13: The oscillator frequency reduces to approximately 18 kHz 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%.

Note 14: Refer to RETS LM1575J for current revision of military RETS/SMD.

(Limits)

μA

μA(Max)

μA

μA(Max)

www.national.com 8

Typical Performance Characteristics (Circuit of Figure 2)

LM1575/LM2575/LM2575HV

Normalized Output Voltage

Dropout Voltage

Line Regulation

1147533

1147532

Current Limit

Quiescent Current

1147534

1147536

1147535

Standby

Quiescent Current

1147537

9 www.national.com