LM2576 [TI]

LM2576/LM2576HV Series SIMPLE SWITCHERÂ® 3A Step-Down Voltage Regulator; LM2576 / LM2576HV系列SIMPLE SWITCHERÂ® 3A降压型稳压器


型号：	LM2576
厂家：	TEXAS INSTRUMENTS
描述：	LM2576/LM2576HV Series SIMPLE SWITCHERÂ® 3A Step-Down Voltage Regulator LM2576 / LM2576HV系列SIMPLE SWITCHERÂ® 3A降压型稳压器稳压器
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中文：	中文翻译
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LM2576, LM2576HV

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SNVS107C –JUNE 1999–REVISED APRIL 2013

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

Check for Samples: LM2576, LM2576HV

FEATURES

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.

•

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

•

Specified 3A Output Current

Wide Input Voltage Range, 40V Up to 60V for

HV Version

Requiring

minimum number of external

components, these regulators are simple to use and

include internal frequency compensation and a fixed-

frequency oscillator.

•

Requires Only 4 External Components

52 kHz Fixed Frequency Internal Oscillator

The LM2576 series offers

high-efficiency

TTL Shutdown Capability, Low Power Standby

Mode

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.

•

High Efficiency

Uses Readily Available Standard Inductors

Thermal Shutdown and Current Limit

Protection

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.

•

P+ Product Enhancement Tested

APPLICATIONS

Other features include a specified ±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.

•

Simple High-Efficiency Step-Down (Buck)

Regulator

•

Efficient Pre-Regulator for Linear Regulators

On-Card Switching Regulators

Positive to Negative Converter (Buck-Boost)

TYPICAL APPLICATION

(Fixed Output Voltage Versions)

Figure 1.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

SIMPLE SWITCHER is a registered trademark of Texas Instruments.

All other trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

LM2576, LM2576HV

SNVS107C –JUNE 1999–REVISED APRIL 2013

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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

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These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

(1)(2)

ABSOLUTE MAXIMUM RATINGS

Maximum Supply Voltage

LM2576

45V

63V

LM2576HV

ON /OFF Pin Input Voltage

Output Voltage to Ground

Power Dissipation

−0.3V ≤ V ≤ +V_IN

−1V

(Steady State)

Internally Limited

−65°C to +150°C

150°C

Storage Temperature Range

Maximum Junction Temperature

Minimum ESD Rating

(C = 100 pF, R = 1.5 kΩ)

2 kV

Lead Temperature

(Soldering, 10 Seconds)

260°C

(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 ensured specific performance limits. For ensured specifications and test

conditions, see ELECTRICAL CHARACTERISTICS ALL OUTPUT VOLTAGE VERSIONS.

(2) If Military/Aerospace specified devices are required, please contact the TI Sales Office/ Distributors for availability and specifications.

OPERATING RATINGS

Temperature Range

LM2576/LM2576HV

LM2576

−40°C ≤ T_J≤ +125°C

Supply Voltage

40V

60V

LM2576HV

ELECTRICAL CHARACTERISTICS LM2576-3.3, LM2576HV-3.3

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

Range.

LM2576-3.3

Units

LM2576HV-3.3

Symbol

Parameter

Conditions

(Limits)

(1)

Typ

Limit

SYSTEM PARAMETERS Test Circuit Figure 21 and Figure 22⁽²⁾

V_OUT

Output Voltage

V_IN= 12V, I_LOAD= 0.5A

Circuit of Figure 21 and Figure 22

3.3

3.234

3.366

V(Min)

V(Max)

Output Voltage

LM2576

6V ≤ V_IN≤ 40V, 0.5A ≤ I_LOAD≤ 3A

Circuit of Figure 21 and Figure 22

3.168/3.135

3.432/3.465

V(Min)

V(Max)

Output Voltage

LM2576HV

6V ≤ V_IN≤ 60V, 0.5A ≤ I_LOAD≤ 3A

Circuit of Figure 21 and Figure 22

3.168/3.135

3.450/3.482

V(Min)

V(Max)

Efficiency

V_IN= 12V, I_LOAD= 3A

(1) All limits specified 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 specified via correlation using standard Statistical Quality Control

(SQC) methods.

(2) 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 Figure 21 and Figure 22, system performance will be as shown in ELECTRICAL

CHARACTERISTICS ALL OUTPUT VOLTAGE VERSIONS.

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ELECTRICAL CHARACTERISTICS LM2576-5.0, LM2576HV-5.0

Specifications with standard type face are for T_J= 25°C, and those with Figure 21 and Figure 22 boldface type apply over

full Operating Temperature Range.

LM2576-5.0

Units

LM2576HV-5.0

Symbol

Parameter

Conditions

(Limits)

(1)

Typ

Limit

SYSTEM PARAMETERS Figure 21 and Figure 22⁽²⁾

V_OUT

Output Voltage

V_IN= 12V, I_LOAD= 0.5A

Circuit of Figure 21 and Figure 22

5.0

4.900

5.100

V(Min)

V(Max)

Output Voltage

LM2576

0.5A ≤ I_LOAD≤ 3A,

8V ≤ V_IN≤ 40V

Circuit of Figure 21 and Figure 22

5.0

4.800/4.750

5.200/5.250

V(Min)

V(Max)

Output Voltage

LM2576HV

0.5A ≤ I_LOAD≤ 3A,

8V ≤ V_IN≤ 60V

Circuit of Figure 21 and Figure 22

4.800/4.750

5.225/5.275

V(Min)

V(Max)

Efficiency

V_IN= 12V, I_LOAD= 3A

(1) All limits specified 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 specified via correlation using standard Statistical Quality Control

(SQC) methods.

(2) 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 Figure 21 and Figure 22, system performance will be as shown in ELECTRICAL

CHARACTERISTICS ALL OUTPUT VOLTAGE VERSIONS.

ELECTRICAL CHARACTERISTICS LM2576-12, LM2576HV-12

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

Range.

LM2576-12

Units

LM2576HV-12

Symbol

Parameter

Conditions

(Limits)

(1)

Typ

Limit

SYSTEM PARAMETERS Test Circuit Figure 21 and Figure 22⁽²⁾

V_OUT

Output Voltage

V_IN= 25V, I_LOAD= 0.5A

Circuit of Figure 21 and Figure 22

V(Min)

V(Max)

11.76

12.24

Output Voltage

LM2576

0.5A ≤ I_LOAD≤ 3A,

15V ≤ V_IN≤ 40V

Circuit of Figure 21 and Figure 22 and

V(Min)

V(Max)

11.52/11.40

12.48/12.60

Output Voltage

LM2576HV

0.5A ≤ I_LOAD≤ 3A,

15V ≤ V_IN≤ 60V

Circuit of Figure 21 and Figure 22

V(Min)

V(Max)

11.52/11.40

12.54/12.66

Efficiency

V_IN= 15V, I_LOAD= 3A

(1) All limits specified 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 specified via correlation using standard Statistical Quality Control

(SQC) methods.

(2) 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 Figure 21 and Figure 22, system performance will be as shown in ELECTRICAL

CHARACTERISTICS ALL OUTPUT VOLTAGE VERSIONS.

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ELECTRICAL CHARACTERISTICS LM2576-15, LM2576HV-15

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

Range.

LM2576-15

Units

LM2576HV-15

Symbol

Parameter

Conditions

(Limits)

(1)

Typ

Limit

SYSTEM PARAMETERS Test Circuit Figure 21 and Figure 22⁽²⁾

V_OUT

Output Voltage

V_IN= 25V, I_LOAD= 0.5A

Circuit of Figure 21 and Figure 22

14.70

15.30

V(Min)

V(Max)

Output Voltage

LM2576

0.5A ≤ I_LOAD≤ 3A,

18V ≤ V_IN≤ 40V

Circuit of Figure 21 and Figure 22

14.40/14.25

15.60/15.75

V(Min)

V(Max)

Output Voltage

LM2576HV

0.5A ≤ I_LOAD≤ 3A,

18V ≤ V_IN≤ 60V

Circuit of Figure 21 and Figure 22

14.40/14.25

15.68/15.83

V(Min)

V(Max)

Efficiency

V_IN= 18V, I_LOAD= 3A

(1) All limits specified 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 specified via correlation using standard Statistical Quality Control

(SQC) methods.

(2) 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 Figure 21 and Figure 22, system performance will be as shown in ELECTRICAL

CHARACTERISTICS ALL OUTPUT VOLTAGE VERSIONS.

ELECTRICAL CHARACTERISTICS LM2576-ADJ, LM2576HV-ADJ

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

Range.

LM2576-ADJ

Units

LM2576HV-ADJ

Symbol

Parameter

Conditions

(Limits)

(1)

Typ

Limit

SYSTEM PARAMETERS Test Circuit Figure 21 and Figure 22⁽²⁾

V_OUT

Feedback Voltage

V_IN= 12V, I_LOAD= 0.5A

V_OUT= 5V,

Circuit of Figure 21 and Figure 22

1.230

1.217

1.243

V(Min)

V(Max)

Feedback Voltage

LM2576

0.5A ≤ I_LOAD≤ 3A,

8V ≤ V_IN≤ 40V

V_OUT= 5V, Circuit of Figure 21 and Figure 22

1.193/1.180

1.267/1.280

V(Min)

V(Max)

Feedback Voltage

LM2576HV

0.5A ≤ I_LOAD≤ 3A,

8V ≤ V_IN≤ 60V

V_OUT= 5V, Circuit of Figure 21 and Figure 22

1.193/1.180

1.273/1.286

V(Min)

V(Max)

Efficiency

V_IN= 12V, I_LOAD= 3A, V_OUT= 5V

(1) All limits specified 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 specified via correlation using standard Statistical Quality Control

(SQC) methods.

(2) 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 Figure 21 and Figure 22, system performance will be as shown in ELECTRICAL

CHARACTERISTICS ALL OUTPUT VOLTAGE VERSIONS.

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ELECTRICAL CHARACTERISTICS ALL OUTPUT VOLTAGE VERSIONS

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

Range. Unless otherwise specified, V_IN= 12V for the 3.3V, 5V, and Adjustable version, V_IN= 25V for the 12V version, and V_IN

= 30V for the 15V version. I_LOAD= 500 mA.

LM2576-XX

Units

LM2576HV-XX

Symbol

Parameter

Conditions

(Limits)

(1)

Typ

Limit

DEVICE PARAMETERS

I_b

Feedback Bias Current

V_OUT= 5V (Adjustable Version Only)

100/500

(2)

f_O

Oscillator Frequency

See

kHz

47/42

58/63

kHz (Min)

kHz (Max)

(3)

V_SAT

Saturation Voltage

Max Duty Cycle (ON)

Current Limit

I_OUT= 3A

1.4

1.8/2.0

V(Max)

(4)

See

%(Min)

(3)(2)

I_CL

See

5.8

4.2/3.5

6.9/7.5

A(Min)

A(Max)

I_L

Output Leakage Current

Quiescent Current

Output = 0V

Output = −1V

mA(Max)

7.5

(5)(6)

(5)

I_Q

See

mA(Max)

I_STBY

Standby Quiescent

Current

ON /OFF Pin = 5V (OFF)

μA

μA(Max)

200

(7)

θ_JA

θ_JC

θ_JA

Thermal Resistance

T Package, Junction to Ambient

T Package, Junction to Case

S Package, Junction to Ambient

(8)

°C/W

(9)

ON /OFF CONTROL Test Circuit Figure 21 and Figure 22

V_IH

V_IL

I_IH

ON /OFF Pin

Logic Input Level

V_OUT= 0V

1.4

1.2

2.2/2.4

1.0/0.8

V(Min)

V(Max)

V_OUT= Nominal Output Voltage

ON /OFF Pin = 5V (OFF)

ON /OFF Pin Input

Current

μA

μA(Max)

I_IL

ON /OFF Pin = 0V (ON)

μA

μA(Max)

(1) All limits specified 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 specified via correlation using standard Statistical Quality Control

(SQC) methods.

(2) The oscillator frequency reduces to approximately 11 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%.

(3) Output pin sourcing current. No diode, inductor or capacitor connected to output.

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

(5) 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.

(6) V_IN= 40V (60V for high voltage version).

(7) 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.

(8) Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically, with ¼ inch leads

soldered to a PC board containing approximately 4 square inches of copper area surrounding the leads.

(9) If the DDPAK/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_JAis 50°C/W, with 1 square inch of copper area, θ_JAis 37°C/W,

and with 1.6 or more square inches of copper area, θ_JAis 32°C/W.

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TYPICAL PERFORMANCE CHARACTERISTICS

(Circuit of Figure 21 and Figure 22)

Normalized Output Voltage

Line Regulation

Figure 2.

Figure 3.

Dropout Voltage

Current Limit

Figure 4.

Figure 5.

Standby

Quiescent Current

Figure 6.

Figure 7.

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TYPICAL PERFORMANCE CHARACTERISTICS (continued)

(Circuit of Figure 21 and Figure 22)

Switch Saturation

Voltage

Oscillator Frequency

Figure 8.

Figure 9.

Efficiency

Minimum Operating Voltage

Figure 10.

Figure 11.

Quiescent Current

vs Duty Cycle

Feedback Voltage

vs Duty Cycle

Figure 12.

Figure 13.

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TYPICAL PERFORMANCE CHARACTERISTICS (continued)

(Circuit of Figure 21 and Figure 22)

Quiescent Current

vs Duty Cycle

Minimum Operating Voltage

Figure 14.

Figure 15.

Feedback Voltage

vs Duty Cycle

Feedback Pin Current

Figure 16.

Figure 17.

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TYPICAL PERFORMANCE CHARACTERISTICS (continued)

(Circuit of Figure 21 and Figure 22)

Maximum Power Dissipation

(DDPAK/TO-263)

Switching Waveforms

V_OUT= 15V

If the DDPAK/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_JAis

50°C/W, with 1 square inch of copper area, θ_JAis 37°C/W, and with

1.6 or more square inches of copper area, θ_JAis 32°C/W.

A: Output Pin Voltage, 50V/div

B: Output Pin Current, 2A/div

C: Inductor Current, 2A/div

D: Output Ripple Voltage, 50 mV/div,

AC-Coupled

Horizontal Time Base: 5 μs/div

Figure 18.

Figure 19.

Load Transient Response

Figure 20.

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TEST CIRCUIT AND LAYOUT GUIDELINES

As in any switching regulator, layout is very important. Rapidly switching currents associated with wiring

inductance generate voltage transients which can cause problems. For minimal inductance and ground loops, the

length of the leads indicated by heavy lines should be kept as short as possible. Single-point grounding (as

indicated) or ground plane construction should be used for best results. When using the Adjustable version,

physically locate the programming resistors near the regulator, to keep the sensitive feedback wiring short.

C_IN— 100 μF, 75V, Aluminum Electrolytic

C_OUT— 1000 μF, 25V, Aluminum Electrolytic

D₁— Schottky, MBR360

L₁— 100 μH, Pulse Eng. PE-92108

R₁— 2k, 0.1%

R₂— 6.12k, 0.1%

Figure 21. Fixed Output Voltage Versions

where

V_REF= 1.23V, R1 between 1k and 5k

Figure 22. Adjustable Output Voltage Version

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LM2576 Series Buck Regulator Design Procedure

PROCEDURE (Fixed Output Voltage Versions)

EXAMPLE (Fixed Output Voltage Versions)

Given:

V_OUT= 5V

V_OUT= Regulated Output Voltage

(3.3V, 5V, 12V, or 15V)

V_IN(Max) = 15V

I_LOAD(Max) = 3A

V_IN(Max) = Maximum Input Voltage

I_LOAD(Max) = Maximum Load Current

1. Inductor Selection (L1)

A. Select the correct Inductor value selection guide from Figure 23, A. Use the selection guide shown in Figure 24.

Figure 24, Figure 25, or Figure 26. (Output voltages of 3.3V, 5V, 12V

or 15V respectively). For other output voltages, see the design

procedure for the adjustable version.

B. From the selection guide, the inductance area intersected by the

15V line and 3A line is L100.

C. Inductor value required is 100 μH. From the table in Figure 23.

Choose AIE 415-0930, Pulse Engineering PE92108, or Renco

RL2444.

B. From the inductor value selection guide, identify the inductance

region intersected by V_IN(Max) and I_LOAD(Max), and note the

inductor code for that region.

C. Identify the inductor value from the inductor code, and select an

appropriate inductor from the table shown in Figure 23. Part

numbers are listed for three inductor manufacturers. The inductor

chosen must be rated for operation at the LM2576 switching

frequency (52 kHz) and for a current rating of 1.15 × I_LOAD. For

additional inductor information, see INDUCTOR SELECTION.

2. Output Capacitor Selection (C_OUT

)

2. Output Capacitor Selection (C_OUT)

A. The value of the output capacitor together with the inductor A. C_OUT= 680 μF to 2000 μF standard aluminum electrolytic.

defines the dominate pole-pair of the switching regulator loop. For

B.Capacitor voltage rating = 20V.

stable operation and an acceptable output ripple voltage,

(approximately 1% of the output voltage) a value between 100 μF

and 470 μF is recommended.

B. The capacitor's voltage rating should be at least 1.5 times greater

than the output voltage. For a 5V regulator, a rating of at least 8V is

appropriate, and a 10V or 15V rating is recommended.

Higher voltage electrolytic capacitors generally have lower ESR

numbers, and for this reason it may be necessary to select a

capacitor rated for a higher voltage than would normally be needed.

3. Catch Diode Selection (D1)

A.The catch-diode current rating must be at least 1.2 times greater A.For this example, a 3A current rating is adequate.

than the maximum load current. Also, if the power supply design

B. Use a 20V 1N5823 or SR302 Schottky diode, or any of the

must withstand a continuous output short, the diode should have a

suggested fast-recovery diodes shown in Table 1.

current rating equal to the maximum current limit of the LM2576. The

most stressful condition for this diode is an overload or shorted

output condition.

B. The reverse voltage rating of the diode should be at least 1.25

times the maximum input voltage.

4. Input Capacitor (C_IN

An aluminum or tantalum electrolytic bypass capacitor located close A 100 μF, 25V aluminum electrolytic capacitor located near the input

to the regulator is needed for stable operation. and ground pins provides sufficient bypassing.

)

4. Input Capacitor (C_IN)

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INDUCTOR VALUE SELECTION GUIDES

(For Continuous Mode Operation)

Figure 23. LM2576(HV)-3.3

Figure 24. LM2576(HV)-5.0

Figure 25. LM2576(HV)-12

Figure 26. LM2576(HV)-15

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(For Continuous Mode Operation)

Figure 27. LM2576(HV)-ADJ

PROCEDURE (Adjustable Output Voltage Versions)

EXAMPLE (Adjustable Output Voltage Versions)

Given:

V_OUT= Regulated Output Voltage

V_OUT= 10V

V_IN(Max) = Maximum Input Voltage

I_LOAD(Max) = Maximum Load Current

F = Switching Frequency (Fixed at 52 kHz)

V_IN(Max) = 25V

I_LOAD(Max) = 3A

F = 52 kHz

1. Programming Output Voltage (Selecting R1 and R2, as shown 1. Programming Output Voltage(Selecting R1 and R2)

in Figure 21 and Figure 22)

Use the following formula to select the appropriate resistor values.

R₁can be between 1k and 5k. (For best temperature coefficient and

stability with time, use 1% metal film resistors)

R₂= 1k (8.13 − 1) = 7.13k, closest 1% value is 7.15k

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(For Continuous Mode Operation)

PROCEDURE (Adjustable Output Voltage Versions)

EXAMPLE (Adjustable Output Voltage Versions)

2. Inductor Selection (L1)

A. Calculate the inductor Volt • microsecond constant, E • T (V • μs), A. Calculate E • T (V • μs)

from the following formula:

B. E • T = 115 V • μs

B. Use the E • T value from the previous formula and match it with

the E • T number on the vertical axis of the Inductor Value

Selection Guide shown in Figure 27.

C. I_LOAD(Max) = 3A

D. Inductance Region = H150

E. Inductor Value = 150 μH Choose from AIEpart #415-0936Pulse

Engineering part #PE-531115, or Renco part #RL2445.

C. On the horizontal axis, select the maximum load current.

D. Identify the inductance region intersected by the E • T value and

the maximum load current value, and note the inductor code for that

region.

E. Identify the inductor value from the inductor code, and select an

appropriate inductor from the table shown in Table 2. Part numbers

are listed for three inductor manufacturers. The inductor chosen

must be rated for operation at the LM2576 switching frequency (52

kHz) and for a current rating of 1.15 × I_LOAD. For additional inductor

information, see INDUCTOR SELECTION.

3. Output Capacitor Selection (C_OUT

)

3. Output Capacitor Selection (C_OUT)

A. The value of the output capacitor together with the inductor

defines the dominate pole-pair of the switching regulator loop. For

stable operation, the capacitor must satisfy the following

requirement:

However, for acceptable output ripple voltage select

_OUT≥ 680 μF

C_OUT= 680 μF electrolytic capacitor

The above formula yields capacitor values between 10 μF and 2200

μF that will satisfy the loop requirements for stable operation. But to

achieve an acceptable output ripple voltage, (approximately 1% of

the output voltage) and transient response, the output capacitor may

need to be several times larger than the above formula yields.

B. The capacitor's voltage rating should be at last 1.5 times greater

than the output voltage. For a 10V regulator, a rating of at least 15V

or more is recommended. Higher voltage electrolytic capacitors

generally have lower ESR numbers, and for this reason it may be

necessary to select a capacitor rate for a higher voltage than would

normally be needed.

4. Catch Diode Selection (D1)

A. The catch-diode current rating must be at least 1.2 times greater A. For this example, a 3.3A current rating is adequate.

than the maximum load current. Also, if the power supply design

B. Use a 30V 31DQ03 Schottky diode, or any of the suggested fast-

must withstand a continuous output short, the diode should have a

recovery diodes in Table 1.

current rating equal to the maximum current limit of the LM2576. The

most stressful condition for this diode is an overload or shorted

output. See Table 1.

B. The reverse voltage rating of the diode should be at least 1.25

times the maximum input voltage.

5. Input Capacitor (C_IN

An aluminum or tantalum electrolytic bypass capacitor located close A 100 μF aluminum electrolytic capacitor located near the input and

to the regulator is needed for stable operation. ground pins provides sufficient bypassing.

)

5. Input Capacitor (C_IN)

To further simplify the buck regulator design procedure, TI is making available computer design software to be

used with the SIMPLE SWITCHER line of switching regulators. Switchers Made Simple (Version 3.3) is

available on a (3½″) diskette for IBM compatible computers from a TI office in your area.

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Table 1. Diode Selection Guide

Schottky

Fast Recovery

V_R

4A–6A

20V

30V

1N5820

MBR320P

SR302

1N5823

1N5821

MBR330

31DQ03

SR303

50WQ03

1N5824

The following

diodes are all

rated to 100V

50WF10

MUR410

HER602

The following

diodes are all

rated to 100V

31DF1

40V

1N5822

MBR340

31DQ04

SR304

MBR340

50WQ04

1N5825

HER302

50V

60V

MBR350

31DQ05

SR305

50WQ05

MBR360

DQ06

50WR06

50SQ060

SR306

Table 2. Inductor Selection by Manufacturer's Part Number

(1)

(2)

(3)

Inductor Code

Inductor Value

47 μH

Schott

Pulse Eng.

PE-53112

PE-92114

PE-92108

PE-53113

PE-52626

PE-52627

PE-53114

PE-52629

PE-53115

PE-53116

PE-53117

PE-53118

PE-53119

PE-53120

PE-53121

PE-53122

Renco

L47

671 26980

671 26990

671 27000

671 27010

671 27020

671 27030

671 27040

671 27050

671 27060

671 27070

671 27080

671 27090

671 27100

671 27110

671 27120

671 27130

RL2442

RL2443

RL2444

RL1954

RL1953

RL1952

RL1951

RL1950

RL2445

RL2446

RL2447

RL1961

RL1960

RL1959

RL1958

RL2448

L68

68 μH

100 μH

150 μH

220 μH

330 μH

470 μH

680 μH

150 μH

220 μH

330 μH

470 μH

680 μH

1000 μH

1500 μH

2200 μH

L100

L150

L220

L330

L470

L680

H150

H220

H330

H470

H680

H1000

H1500

H2200

(1) Schott Corporation, (612) 475-1173, 1000 Parkers Lake Road, Wayzata, MN 55391.

(2) Pulse Engineering, (619) 674-8100, P.O. Box 12235, San Diego, CA 92112.

(3) Renco Electronics Incorporated, (516) 586-5566, 60 Jeffryn Blvd. East, Deer Park, NY 11729.

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APPLICATION HINTS

INPUT CAPACITOR (C_IN)

To maintain stability, the regulator input pin must be bypassed with at least a 100 μF electrolytic capacitor. The

capacitor's leads must be kept short, and located near the regulator.

If the operating temperature range includes temperatures below −25°C, the input capacitor value may need to be

larger. With most electrolytic capacitors, the capacitance value decreases and the ESR increases with lower

temperatures and age. Paralleling a ceramic or solid tantalum capacitor will increase the regulator stability at cold

temperatures. For maximum capacitor operating lifetime, the capacitor's RMS ripple current rating should be

greater than

(1)

INDUCTOR SELECTION

All switching regulators have two basic modes of operation: continuous and discontinuous. The difference

between the two types relates to the inductor current, whether it is flowing continuously, or if it drops to zero for a

period of time in the normal switching cycle. Each mode has distinctively different operating characteristics,

which can affect the regulator performance and requirements.

The LM2576 (or any of the SIMPLE SWITCHER family) can be used for both continuous and discontinuous

modes of operation.

The inductor value selection guides in Figure 23 through Figure 27 were designed for buck regulator designs of

the continuous inductor current type. When using inductor values shown in the inductor selection guide, the

peak-to-peak inductor ripple current will be approximately 20% to 30% of the maximum DC current. With

relatively heavy load currents, the circuit operates in the continuous mode (inductor current always flowing), but

under light load conditions, the circuit will be forced to the discontinuous mode (inductor current falls to zero for a

period of time). This discontinuous mode of operation is perfectly acceptable. For light loads (less than

approximately 300 mA) it may be desirable to operate the regulator in the discontinuous mode, primarily because

of the lower inductor values required for the discontinuous mode.

The selection guide chooses inductor values suitable for continuous mode operation, but if the inductor value

chosen is prohibitively high, the designer should investigate the possibility of discontinuous operation. The

computer design software Switchers Made Simple will provide all component values for discontinuous (as well

as continuous) mode of operation.

Inductors are available in different styles such as pot core, toriod, E-frame, bobbin core, and so on, as well as

different core materials, such as ferrites and powdered iron. The least expensive, the bobbin core type, consists

of wire wrapped on a ferrite rod core. This type of construction makes for an inexpensive inductor, but since the

magnetic flux is not completely contained within the core, it generates more electromagnetic interference (EMI).

This EMI can cause problems in sensitive circuits, or can give incorrect scope readings because of induced

voltages in the scope probe.

The inductors listed in the selection chart include ferrite pot core construction for AIE, powdered iron toroid for

Pulse Engineering, and ferrite bobbin core for Renco.

An inductor should not be operated beyond its maximum rated current because it may saturate. When an

inductor begins to saturate, the inductance decreases rapidly and the inductor begins to look mainly resistive (the

DC resistance of the winding). This will cause the switch current to rise very rapidly. Different inductor types have

different saturation characteristics, and this should be kept in mind when selecting an inductor.

The inductor manufacturer's data sheets include current and energy limits to avoid inductor saturation.

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INDUCTOR RIPPLE CURRENT

When the switcher is operating in the continuous mode, the inductor current waveform ranges from a triangular

to a sawtooth type of waveform (depending on the input voltage). For a given input voltage and output voltage,

the peak-to-peak amplitude of this inductor current waveform remains constant. As the load current rises or falls,

the entire sawtooth current waveform also rises or falls. The average DC value of this waveform is equal to the

DC load current (in the buck regulator configuration).

If the load current drops to a low enough level, the bottom of the sawtooth current waveform will reach zero, and

the switcher will change to a discontinuous mode of operation. This is a perfectly acceptable mode of operation.

Any buck switching regulator (no matter how large the inductor value is) will be forced to run discontinuous if the

load current is light enough.

OUTPUT CAPACITOR

An output capacitor is required to filter the output voltage and is needed for loop stability. The capacitor should

be located near the LM2576 using short pc board traces. Standard aluminum electrolytics are usually adequate,

but low ESR types are recommended for low output ripple voltage and good stability. The ESR of a capacitor

depends on many factors, some which are: the value, the voltage rating, physical size and the type of

construction. In general, low value or low voltage (less than 12V) electrolytic capacitors usually have higher ESR

numbers.

The amount of output ripple voltage is primarily a function of the ESR (Equivalent Series Resistance) of the

output capacitor and the amplitude of the inductor ripple current (ΔI_IND). See INDUCTOR RIPPLE CURRENT.

The lower capacitor values (220 μF–1000 μF) will allow typically 50 mV to 150 mV of output ripple voltage, while

larger-value capacitors will reduce the ripple to approximately 20 mV to 50 mV.

Output Ripple Voltage = (ΔI_IND) (ESR of C_OUT

)

(2)

To further reduce the output ripple voltage, several standard electrolytic capacitors may be paralleled, or a

higher-grade capacitor may be used. Such capacitors are often called “high-frequency,” “low-inductance,” or

“low-ESR.” These will reduce the output ripple to 10 mV or 20 mV. However, when operating in the continuous

mode, reducing the ESR below 0.03Ω can cause instability in the regulator.

Tantalum capacitors can have a very low ESR, and should be carefully evaluated if it is the only output capacitor.

Because of their good low temperature characteristics, a tantalum can be used in parallel with aluminum

electrolytics, with the tantalum making up 10% or 20% of the total capacitance.

The capacitor's ripple current rating at 52 kHz should be at least 50% higher than the peak-to-peak inductor

ripple current.

CATCH DIODE

Buck regulators require a diode to provide a return path for the inductor current when the switch is off. This diode

should be located close to the LM2576 using short leads and short printed circuit traces.

Because of their fast switching speed and low forward voltage drop, Schottky diodes provide the best efficiency,

especially in low output voltage switching regulators (less than 5V). Fast-Recovery, High-Efficiency, or Ultra-Fast

Recovery diodes are also suitable, but some types with an abrupt turn-off characteristic may cause instability and

EMI problems. A fast-recovery diode with soft recovery characteristics is a better choice. Standard 60 Hz diodes

(e.g., 1N4001 or 1N5400, and so on) are also not suitable. See Table 1 for Schottky and “soft” fast-recovery

diode selection guide.

OUTPUT VOLTAGE RIPPLE AND TRANSIENTS

The output voltage of a switching power supply will contain a sawtooth ripple voltage at the switcher frequency,

typically about 1% of the output voltage, and may also contain short voltage spikes at the peaks of the sawtooth

waveform.

The output ripple voltage is due mainly to the inductor sawtooth ripple current multiplied by the ESR of the output

capacitor. (See INDUCTOR SELECTION)

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The voltage spikes are present because of the the fast switching action of the output switch, and the parasitic

inductance of the output filter capacitor. To minimize these voltage spikes, special low inductance capacitors can

be used, and their lead lengths must be kept short. Wiring inductance, stray capacitance, as well as the scope

probe used to evaluate these transients, all contribute to the amplitude of these spikes.

An additional small LC filter (20 μH & 100 μF) can be added to the output (as shown in Figure 33) to further

reduce the amount of output ripple and transients. A 10 × reduction in output ripple voltage and transients is

possible with this filter.

FEEDBACK CONNECTION

The LM2576 (fixed voltage versions) feedback pin must be wired to the output voltage point of the switching

power supply. When using the adjustable version, physically locate both output voltage programming resistors

near the LM2576 to avoid picking up unwanted noise. Avoid using resistors greater than 100 kΩ because of the

increased chance of noise pickup.

ON /OFF INPUT

For normal operation, the ON /OFF pin should be grounded or driven with a low-level TTL voltage (typically

below 1.6V). To put the regulator into standby mode, drive this pin with a high-level TTL or CMOS signal. The

ON /OFF pin can be safely pulled up to +V_INwithout a resistor in series with it. The ON /OFF pin should not be

left open.

GROUNDING

To maintain output voltage stability, the power ground connections must be low-impedance (see Figure 21 and

Figure 22). For the 5-lead TO-220 and DDPAK/TO-263 style package, both the tab and pin 3 are ground and

either connection may be used, as they are both part of the same copper lead frame.

HEAT SINK/THERMAL CONSIDERATIONS

In many cases, only a small heat sink is required to keep the LM2576 junction temperature within the allowed

operating range. For each application, to determine whether or not a heat sink will be required, the following

must be identified:

1. Maximum ambient temperature (in the application).

2. Maximum regulator power dissipation (in application).

3. Maximum allowed junction temperature (125°C for the LM2576). For a safe, conservative design, a

temperature approximately 15°C cooler than the maximum temperatures should be selected.

4. LM2576 package thermal resistances θ_JAand θ_JC.

Total power dissipated by the LM2576 can be estimated as follows:

P_D= (V_IN)(I_Q) + (V_O/V_IN)(I_LOAD)(V_SAT

)

where

•

I_Q(quiescent current) and V_SATcan be found in TYPICAL PERFORMANCE CHARACTERISTICS shown

previously,

•

V_INis the applied minimum input voltage, V_Ois the regulated output voltage,

and I_LOADis the load current.

(3)

(4)

The dynamic losses during turn-on and turn-off are negligible if a Schottky type catch diode is used.

When no heat sink is used, the junction temperature rise can be determined by the following:

ΔT_J= (P_D) (θ_JA)

To arrive at the actual operating junction temperature, add the junction temperature rise to the maximum ambient

temperature.

T_J= ΔT_J+ T_A

(5)

If the actual operating junction temperature is greater than the selected safe operating junction temperature

determined in step 3, then a heat sink is required.

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When using a heat sink, the junction temperature rise can be determined by the following:

ΔT_J= (P_D) (θ_JC+ θ_interface+ θ_{Heat sink}

)

(6)

(7)

The operating junction temperature will be:

T_J= T_A+ ΔT_J

As in Equation 14, if the actual operating junction temperature is greater than the selected safe operating

junction temperature, then a larger heat sink is required (one that has a lower thermal resistance).

Included on the Switcher Made Simple design software is a more precise (non-linear) thermal model that can

be used to determine junction temperature with different input-output parameters or different component values.

It can also calculate the heat sink thermal resistance required to maintain the regulators junction temperature

below the maximum operating temperature.

Additional Applications

INVERTING REGULATOR

Figure 28 shows a LM2576-12 in a buck-boost configuration to generate a negative 12V output from a positive

input voltage. This circuit bootstraps the regulator's ground pin to the negative output voltage, then by grounding

the feedback pin, the regulator senses the inverted output voltage and regulates it to −12V.

For an input voltage of 12V or more, the maximum available output current in this configuration is approximately

700 mA. At lighter loads, the minimum input voltage required drops to approximately 4.7V.

The switch currents in this buck-boost configuration are higher than in the standard buck-mode design, thus

lowering the available output current. Also, the start-up input current of the buck-boost converter is higher than

the standard buck-mode regulator, and this may overload an input power source with a current limit less than 5A.

Using a delayed turn-on or an undervoltage lockout circuit (described in NEGATIVE BOOST REGULATOR)

would allow the input voltage to rise to a high enough level before the switcher would be allowed to turn on.

Because of the structural differences between the buck and the buck-boost regulator topologies, the buck

regulator design procedure section can not be used to select the inductor or the output capacitor. The

recommended range of inductor values for the buck-boost design is between 68 μH and 220 μH, and the output

capacitor values must be larger than what is normally required for buck designs. Low input voltages or high

output currents require a large value output capacitor (in the thousands of micro Farads).

The peak inductor current, which is the same as the peak switch current, can be calculated from the following

formula:

where

•

f_osc= 52 kHz

(8)

Under normal continuous inductor current operating conditions, the minimum V_INrepresents the worst case.

Select an inductor that is rated for the peak current anticipated.

Figure 28. Inverting Buck-Boost Develops −12V

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Also, the maximum voltage appearing across the regulator is the absolute sum of the input and output voltage.

For a −12V output, the maximum input voltage for the LM2576 is +28V, or +48V for the LM2576HV.

The Switchers Made Simple (version 3.0) design software can be used to determine the feasibility of regulator

designs using different topologies, different input-output parameters, different components, and so on.

NEGATIVE BOOST REGULATOR

Another variation on the buck-boost topology is the negative boost configuration. The circuit in Figure 29 accepts

an input voltage ranging from −5V to −12V and provides a regulated −12V output. Input voltages greater than

−12V will cause the output to rise above −12V, but will not damage the regulator.

Feedback

OUT

2200 mF

LM2576-12

Output

LOW ESR

1N5820

GND

ON/OFF

100 mF

OUT

= -12V

100 mH

-V

-5V to -12V

Typical Load Current

400 mA for V_IN= −5.2V

750 mA for V_IN= −7V

Heat sink may be required.

Figure 29. Negative Boost

Because of the boosting function of this type of regulator, the switch current is relatively high, especially at low

input voltages. Output load current limitations are a result of the maximum current rating of the switch. Also,

boost regulators can not provide current limiting load protection in the event of a shorted load, so some other

means (such as a fuse) may be necessary.

UNDERVOLTAGE LOCKOUT

In some applications it is desirable to keep the regulator off until the input voltage reaches a certain threshold. An

undervoltage lockout circuit which accomplishes this task is shown in Figure 30, while Figure 31 shows the same

circuit applied to a buck-boost configuration. These circuits keep the regulator off until the input voltage reaches

a predetermined level.

V_TH≈ V_Z1+ 2V_BE(Q1)

Complete circuit not shown.

Figure 30. Undervoltage Lockout for Buck Circuit

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Complete circuit not shown (see Figure 28).

Figure 31. Undervoltage Lockout

for Buck-Boost Circuit

DELAYED STARTUP

The ON /OFF pin can be used to provide a delayed startup feature as shown in Figure 32. With an input voltage

of 20V and for the part values shown, the circuit provides approximately 10 ms of delay time before the circuit

begins switching. Increasing the RC time constant can provide longer delay times. But excessively large RC time

constants can cause problems with input voltages that are high in 60 Hz or 120 Hz ripple, by coupling the ripple

into the ON /OFF pin.

ADJUSTABLE OUTPUT, LOW-RIPPLE POWER SUPPLY

A 3A power supply that features an adjustable output voltage is shown in Figure 33. An additional L-C filter that

reduces the output ripple by a factor of 10 or more is included in this circuit.

Complete circuit not shown.

Figure 32. Delayed Startup

Figure 33. 1.2V to 55V Adjustable 3A Power Supply with Low Output Ripple

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DEFINITION OF TERMS

BUCK REGULATORA switching regulator topology in which a higher voltage is converted to a lower voltage.

Also known as a step-down switching regulator.

BUCK-BOOST REGULATORA switching regulator topology in which a positive voltage is converted to a

negative voltage without a transformer.

DUTY CYCLE (D)Ratio of the output switch's on-time to the oscillator period.

(9)

CATCH DIODE OR CURRENT STEERING DIODEThe diode which provides a return path for the load current

when the LM2576 switch is OFF.

EFFICIENCY (η)The proportion of input power actually delivered to the load.

(10)

CAPACITOR EQUIVALENT SERIES RESISTANCE (ESR)The purely resistive component of a real capacitor's

impedance (see Figure 34). It causes power loss resulting in capacitor heating, which directly affects the

capacitor's operating lifetime. When used as a switching regulator output filter, higher ESR values result in

higher output ripple voltages.

Figure 34. Simple Model of a Real Capacitor

Most standard aluminum electrolytic capacitors in the 100 μF–1000 μF range have 0.5Ω to

0.1Ω ESR. Higher-grade capacitors (“low-ESR”, “high-frequency”, or “low-inductance”) in the

100 μF–1000 μF range generally have ESR of less than 0.15Ω.

EQUIVALENT SERIES INDUCTANCE (ESL)The pure inductance component of a capacitor (see Figure 34).

The amount of inductance is determined to a large extent on the capacitor's construction. In a buck

regulator, this unwanted inductance causes voltage spikes to appear on the output.

OUTPUT RIPPLE VOLTAGEThe AC component of the switching regulator's output voltage. It is usually

dominated by the output capacitor's ESR multiplied by the inductor's ripple current (ΔI_IND). The peak-to-

peak value of this sawtooth ripple current can be determined by reading the INDUCTOR RIPPLE

CURRENT section.

CAPACITOR RIPPLE CURRENTRMS value of the maximum allowable alternating current at which a capacitor

can be operated continuously at a specified temperature.

STANDBY QUIESCENT CURRENT (I_STBY)Supply current required by the LM2576 when in the standby mode

(ON /OFF pin is driven to TTL-high voltage, thus turning the output switch OFF).

INDUCTOR RIPPLE CURRENT (ΔI_IND)The peak-to-peak value of the inductor current waveform, typically a

sawtooth waveform when the regulator is operating in the continuous mode (vs. discontinuous mode).

CONTINUOUS/DISCONTINUOUS MODE OPERATIONRelates to the inductor current. In the continuous mode,

the inductor current is always flowing and never drops to zero, vs. the discontinuous mode, where the

inductor current drops to zero for a period of time in the normal switching cycle.

INDUCTOR SATURATIONThe condition which exists when an inductor cannot hold any more magnetic flux.

When an inductor saturates, the inductor appears less inductive and the resistive component dominates.

Inductor current is then limited only by the DC resistance of the wire and the available source current.

OPERATING VOLT MICROSECOND CONSTANT (E•T_op)The product (in VoIt•μs) of the voltage applied to the

inductor and the time the voltage is applied. This E•T_opconstant is a measure of the energy handling

capability of an inductor and is dependent upon the type of core, the core area, the number of turns, and

the duty cycle.

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Connection Diagrams

(XX indicates output voltage option.)

Top View

Figure 35. Straight Leads

5-Lead TO-220 (T) Package

LM2576T-XX or LM2576HVT-XX

See Package Number KC0005A

Top View

Figure 36. DDPAK/TO-263 (S) Package

5-Lead Surface-Mount Package

LM2576S-XX or LM2576HVS-XX

See Package Number KTT0005B

LM2576SX-XX or LM2576HVSX-XX

See Package Number KTT0005B

Top View

Figure 37. Bent, Staggered Leads

5-Lead TO-220 (T) Package

LM2576T-XX Flow LB03

or LM2576HVT-XX Flow LB03

See Package Number NDH0005D

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REVISION HISTORY

Changes from Revision B (April 2013) to Revision C

Page

•

Changed layout of National Data Sheet to TI format .......................................................................................................... 24

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PACKAGE OPTION ADDENDUM

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1-Nov-2013

PACKAGING INFORMATION

Orderable Device

LM2576HVS-12

Status Package Type Package Pins Package

Eco Plan

Lead/Ball Finish

MSL Peak Temp

Op Temp (°C)

-40 to 125

Device Marking

Samples

Drawing

Qty

(1)

(2)

(6)

(3)

(4/5)

NRND

DDPAK/

TO-263

KTT

TBD

Call TI

CU SN

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CU SN

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Call TI

Level-3-245C-168 HR

Call TI

LM2576

HVS-12 P+

LM2576HVS-12/NOPB

LM2576HVS-3.3

ACTIVE

NRND

DDPAK/

TO-263

KTT

Pb-Free (RoHS

Exempt)

LM2576

HVS-12 P+

DDPAK/

TO-263

TBD

LM2576

HVS-3.3 P+

LM2576HVS-3.3/NOPB

LM2576HVS-5.0

ACTIVE

NRND

DDPAK/

TO-263

Pb-Free (RoHS

Exempt)

Level-3-245C-168 HR

Call TI

LM2576

HVS-3.3 P+

DDPAK/

TO-263

TBD

LM2576

HVS-5.0 P+

LM2576HVS-5.0/NOPB

LM2576HVS-ADJ

ACTIVE

NRND

DDPAK/

TO-263

Pb-Free (RoHS

Exempt)

Level-3-245C-168 HR

Call TI

LM2576

HVS-5.0 P+

DDPAK/

TO-263

TBD

LM2576

HVS-ADJ P+

LM2576HVS-ADJ/NOPB

LM2576HVSX-12

ACTIVE

NRND

DDPAK/

TO-263

Pb-Free (RoHS

Exempt)

Level-3-245C-168 HR

Call TI

LM2576

HVS-ADJ P+

DDPAK/

TO-263

500

TBD

LM2576

HVS-12 P+

LM2576HVSX-12/NOPB

LM2576HVSX-3.3/NOPB

LM2576HVSX-5.0

ACTIVE

NRND

DDPAK/

TO-263

Pb-Free (RoHS

Exempt)

Level-3-245C-168 HR

Call TI

LM2576

HVS-12 P+

DDPAK/

TO-263

Pb-Free (RoHS

Exempt)

LM2576

HVS-3.3 P+

DDPAK/

TO-263

TBD

LM2576

HVS-5.0 P+

LM2576HVSX-5.0/NOPB

LM2576HVSX-ADJ

LM2576HVSX-ADJ/NOPB

LM2576HVT-12

ACTIVE

NRND

DDPAK/

TO-263

Pb-Free (RoHS

Exempt)

Level-3-245C-168 HR

Call TI

LM2576

HVS-5.0 P+

DDPAK/

TO-263

TBD

LM2576

HVS-ADJ P+

ACTIVE

NRND

DDPAK/

TO-263

Pb-Free (RoHS

Exempt)

Level-3-245C-168 HR

Call TI

LM2576

HVS-ADJ P+

TO-220

TBD

LM2576HVT

-12 P+

LM2576HVT-12/LF03

ACTIVE

TO-220

NDH

Green (RoHS

& no Sb/Br)

Level-1-NA-UNLIM

LM2576HVT

-12 P+

Addendum-Page 1

PACKAGE OPTION ADDENDUM

www.ti.com

1-Nov-2013

Orderable Device

Status Package Type Package Pins Package

Eco Plan

Lead/Ball Finish

MSL Peak Temp

Op Temp (°C)

-40 to 125

Device Marking

Samples

Drawing

Qty

(1)

(2)

(6)

(3)

(4/5)

LM2576HVT-12/NOPB

LM2576HVT-15

ACTIVE

TO-220

Green (RoHS

& no Sb/Br)

CU SN

Call TI

CU SN

Call TI

CU SN

Call TI

CU SN

Call TI

CU SN

Call TI

Level-1-NA-UNLIM

LM2576HVT

-12 P+

NRND

NDH

TBD

Call TI

-40 to 125

LM2576HVT

-15 P+

LM2576HVT-15/LB03

LM2576HVT-15/LF03

LM2576HVT-15/NOPB

LM2576HVT-5.0

TBD

Call TI

LM2576HVT

-15 P+

ACTIVE

NRND

Green (RoHS

& no Sb/Br)

Level-1-NA-UNLIM

Call TI

LM2576HVT

-15 P+

Green (RoHS

& no Sb/Br)

-40 to 125

LM2576HVT

-15 P+

TBD

LM2576HVT

-5.0 P+

LM2576HVT-5.0/LB03

LM2576HVT-5.0/LF02

LM2576HVT-5.0/LF03

LM2576HVT-5.0/NOPB

LM2576HVT-ADJ

NRND

NDH

NEB

NDH

TBD

Call TI

LM2576HVT

-5.0 P+

ACTIVE

NRND

Green (RoHS

& no Sb/Br)

Level-1-NA-UNLIM

Call TI

LM2576HVT

-5.0 P+

Green (RoHS

& no Sb/Br)

LM2576HVT

-5.0 P+

Green (RoHS

& no Sb/Br)

-40 to 125

LM2576HVT

-5.0 P+

TBD

LM2576HVT

-ADJ P+

LM2576HVT-ADJ/LB03

LM2576HVT-ADJ/LF03

LM2576HVT-ADJ/NOPB

LM2576S-12

NRND

NDH

TBD

Call TI

LM2576HVT

-ADJ P+

ACTIVE

NRND

Green (RoHS

& no Sb/Br)

Level-1-NA-UNLIM

Call TI

LM2576HVT

-ADJ P+

Green (RoHS

& no Sb/Br)

-40 to 125

LM2576HVT

-ADJ P+

DDPAK/

TO-263

KTT

TBD

LM2576S

-12 P+

LM2576S-12/NOPB

LM2576S-3.3/NOPB

LM2576S-5.0

ACTIVE

NRND

DDPAK/

TO-263

Pb-Free (RoHS

Exempt)

Level-3-245C-168 HR

Call TI

LM2576S

-12 P+

DDPAK/

TO-263

Pb-Free (RoHS

Exempt)

LM2576S

-3.3 P+

DDPAK/

TO-263

TBD

LM2576S

-5.0 P+

Addendum-Page 2

PACKAGE OPTION ADDENDUM

www.ti.com

1-Nov-2013

Orderable Device

Status Package Type Package Pins Package

Eco Plan

Lead/Ball Finish

MSL Peak Temp

Op Temp (°C)

-40 to 125

Device Marking

Samples

Drawing

Qty

(1)

(2)

(6)

(3)

(4/5)

LM2576S-5.0/NOPB

LM2576S-ADJ

ACTIVE

DDPAK/

TO-263

KTT

Pb-Free (RoHS

Exempt)

CU SN

Call TI

CU SN

Call TI

CU SN

Call TI

CU SN

Call TI

CU SN

Level-3-245C-168 HR

LM2576S

-5.0 P+

ACTIVE

NRND

DDPAK/

TO-263

KTT

TBD

Call TI

LM2576S

-ADJ P+

LM2576S-ADJ/NOPB

LM2576SX-3.3/NOPB

LM2576SX-5.0/NOPB

LM2576SX-ADJ/NOPB

LM2576T-12

DDPAK/

TO-263

500

Pb-Free (RoHS

Exempt)

Level-3-245C-168 HR

Call TI

LM2576S

-ADJ P+

DDPAK/

TO-263

Pb-Free (RoHS

Exempt)

LM2576S

-3.3 P+

DDPAK/

TO-263

Pb-Free (RoHS

Exempt)

LM2576S

-5.0 P+

DDPAK/

TO-263

Pb-Free (RoHS

Exempt)

LM2576S

-ADJ P+

TO-220

TBD

LM2576T

-12 P+

LM2576T-12/LB03

LM2576T-12/LF03

LM2576T-12/NOPB

LM2576T-15/LF03

LM2576T-15/NOPB

LM2576T-3.3/LB03

LM2576T-3.3/LF03

LM2576T-3.3/NOPB

LM2576T-5.0

NRND

NDH

TBD

Call TI

LM2576T

-12 P+

ACTIVE

NRND

Green (RoHS

& no Sb/Br)

Level-1-NA-UNLIM

Call TI

LM2576T

-12 P+

Green (RoHS

& no Sb/Br)

-40 to 125

LM2576T

-12 P+

NDH

Green (RoHS

& no Sb/Br)

LM2576T

-15 P+

Green (RoHS

& no Sb/Br)

LM2576T

-15 P+

NDH

TBD

LM2576T

-3.3 P+

ACTIVE

NRND

Green (RoHS

& no Sb/Br)

Level-1-NA-UNLIM

Call TI

LM2576T

-3.3 P+

Green (RoHS

& no Sb/Br)

-40 to 125

LM2576T

-3.3 P+

TBD

LM2576T

-5.0 P+

LM2576T-5.0/LB03

LM2576T-5.0/LF02

NRND

NDH

NEB

TBD

Call TI

LM2576T

-5.0 P+

ACTIVE

Green (RoHS

& no Sb/Br)

Level-1-NA-UNLIM

LM2576T

-5.0 P+

Addendum-Page 3

PACKAGE OPTION ADDENDUM

www.ti.com

1-Nov-2013

Orderable Device

Status Package Type Package Pins Package

Eco Plan

Lead/Ball Finish

MSL Peak Temp

Op Temp (°C)

Device Marking

Samples

Drawing

Qty

(1)

(2)

(6)

(3)

(4/5)

LM2576T-5.0/LF03

LM2576T-5.0/NOPB

LM2576T-ADJ

ACTIVE

TO-220

NDH

Green (RoHS

& no Sb/Br)

CU SN

Call TI

CU SN

Level-1-NA-UNLIM

Call TI

LM2576T

-5.0 P+

ACTIVE

NRND

Green (RoHS

& no Sb/Br)

-40 to 125

LM2576T

-5.0 P+

TBD

LM2576T

-ADJ P+

LM2576T-ADJ/LB03

LM2576T-ADJ/LF02

LM2576T-ADJ/LF03

LM2576T-ADJ/NOPB

NRND

NDH

NEB

NDH

TBD

Call TI

LM2576T

-ADJ P+

ACTIVE

Green (RoHS

& no Sb/Br)

Level-1-NA-UNLIM

LM2576T

-ADJ P+

Green (RoHS

& no Sb/Br)

LM2576T

-ADJ P+

Green (RoHS

& no Sb/Br)

-40 to 125

LM2576T

-ADJ P+

⁽¹⁾The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

⁽²⁾Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability

information and additional product content details.

TBD: The Pb-Free/Green conversion plan has not been defined.

Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that

lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.

Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between

the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.

Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight

in homogeneous material)

⁽³⁾MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

⁽⁴⁾There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.

⁽⁵⁾Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation

of the previous line and the two combined represent the entire Device Marking for that device.

Addendum-Page 4

PACKAGE OPTION ADDENDUM

www.ti.com

1-Nov-2013

⁽⁶⁾Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish

value exceeds the maximum column width.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information

provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and

continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.

TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

Addendum-Page 5

PACKAGE MATERIALS INFORMATION

www.ti.com

23-Sep-2013

TAPE AND REEL INFORMATION

*All dimensions are nominal

Device

Package Package Pins

Type Drawing

SPQ

Reel

Pin1

Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant

(mm) W1 (mm)

LM2576HVSX-12

DDPAK/

TO-263

KTT

500

330.0

24.4

10.75 14.85

5.0

16.0

24.0

LM2576HVSX-12/NOPB DDPAK/

TO-263

LM2576HVSX-3.3/NOPB DDPAK/

TO-263

LM2576HVSX-5.0

DDPAK/

TO-263

LM2576HVSX-5.0/NOPB DDPAK/

TO-263

LM2576HVSX-ADJ

DDPAK/

TO-263

LM2576HVSX-ADJ/NOPB DDPAK/

TO-263

LM2576SX-3.3/NOPB

DDPAK/

TO-263

LM2576SX-5.0/NOPB

DDPAK/

TO-263

LM2576SX-ADJ/NOPB DDPAK/

TO-263

Pack Materials-Page 1

PACKAGE MATERIALS INFORMATION

www.ti.com

23-Sep-2013

*All dimensions are nominal

Device

Package Type Package Drawing Pins

SPQ

Length (mm) Width (mm) Height (mm)

LM2576HVSX-12

DDPAK/TO-263

KTT

500

367.0

45.0

LM2576HVSX-12/NOPB

LM2576HVSX-3.3/NOPB DDPAK/TO-263

LM2576HVSX-5.0 DDPAK/TO-263

LM2576HVSX-5.0/NOPB DDPAK/TO-263

LM2576HVSX-ADJ DDPAK/TO-263

LM2576HVSX-ADJ/NOPB DDPAK/TO-263

LM2576SX-3.3/NOPB

LM2576SX-5.0/NOPB

LM2576SX-ADJ/NOPB

DDPAK/TO-263

Pack Materials-Page 2

MECHANICAL DATA

NDH0005D

www.ti.com

MECHANICAL DATA

KTT0005B

TS5B (Rev D)

BOTTOM SIDE OF PACKAGE

www.ti.com

MECHANICAL DATA

NEB0005B

www.ti.com

IMPORTANT NOTICE

Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other

changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest

issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and

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supplied at the time of order acknowledgment.

TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms

and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary

to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily

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TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and

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Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265

LM2576 [TI]

相关型号：

LM2576-12

LM2576-12

LM2576-12BT

LM2576-12BT-LB02

LM2576-12BT-LB03

LM2576-12BT⒂

LM2576-12BU

LM2576-12BUT&R

LM2576-12MDC

LM2576-12MWC

LM2576-12WT

LM2576-12WU