LM2576T-3.3 - Texas Instruments High-Performance Analog

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

1FEATURES DESCRIPTION

The LM2576 series of regulators are monolithic

23• 3.3V, 5V, 12V, 15V, and Adjustable Output integrated circuits that provide all the active functions

Versions for a step-down (buck) switching regulator, capable of

• Adjustable Version Output Voltage driving 3A load with excellent line and load regulation.

Range,1.23V to 37V (57V for HV Version) ±4% These devices are available in fixed output voltages

Max Over Line and Load Conditions of 3.3V, 5V, 12V, 15V, and an adjustable output

version.

• Specified 3A Output Current

• Wide Input Voltage Range, 40V Up to 60V for Requiring a minimum number of external

HV Version components, these regulators are simple to use and

include internal frequency compensation and a fixed-

• Requires Only 4 External Components frequency oscillator.

• 52 kHz Fixed Frequency Internal Oscillator The LM2576 series offers a high-efficiency

• TTL Shutdown Capability, Low Power Standby replacement for popular three-terminal linear

Mode regulators. It substantially reduces the size of the

• High Efficiency heat sink, and in some cases no heat sink is

required.

• Uses Readily Available Standard Inductors

• Thermal Shutdown and Current Limit A standard series of inductors optimized for use with

Protection the LM2576 are available from several different

manufacturers. This feature greatly simplifies the

• P+ Product Enhancement Tested design of switch-mode power supplies.

APPLICATIONS Other features include a specified ±4% tolerance on

output voltage within specified input voltages and

• Simple High-Efficiency Step-Down (Buck) output load conditions, and ±10% on the oscillator

Regulator frequency. External shutdown is included, featuring

• Efficient Pre-Regulator for Linear Regulators 50 μA (typical) standby current. The output switch

includes cycle-by-cycle current limiting, as well as

• On-Card Switching Regulators thermal shutdown for full protection under fault

• Positive to Negative Converter (Buck-Boost) conditions.

TYPICAL APPLICATION

(Fixed Output Voltage Versions)

Figure 1.

1Please 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.

2SIMPLE SWITCHER is a registered trademark of Texas Instruments.

3All other trademarks are the property of their respective owners.

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.

ABSOLUTE MAXIMUM RATINGS (1)(2)

Maximum Supply Voltage LM2576 45V

LM2576HV 63V

ON /OFF Pin Input Voltage −0.3V ≤V≤+VIN

Output Voltage to Ground (Steady State) −1V

Power Dissipation Internally Limited

Storage Temperature Range −65°C to +150°C

Maximum Junction Temperature 150°C

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 −40°C ≤TJ≤+125°C

Supply Voltage LM2576 40V

LM2576HV 60V

ELECTRICAL CHARACTERISTICS LM2576-3.3, LM2576HV-3.3

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

Range. LM2576-3.3 Units

LM2576HV-3.3

Symbol Parameter Conditions (Limits)

Typ Limit (1)

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

VOUT Output Voltage VIN = 12V, ILOAD = 0.5A 3.3 V

Circuit of Figure 21 and Figure 22 3.234 V(Min)

3.366 V(Max)

VOUT Output Voltage 6V ≤VIN ≤40V, 0.5A ≤ILOAD ≤3A 3.3 V

LM2576 Circuit of Figure 21 and Figure 22 3.168/3.135 V(Min)

3.432/3.465 V(Max)

VOUT Output Voltage 6V ≤VIN ≤60V, 0.5A ≤ILOAD ≤3A 3.3 V

LM2576HV Circuit of Figure 21 and Figure 22 3.168/3.135 V(Min)

3.450/3.482 V(Max)

ηEfficiency VIN = 12V, ILOAD = 3A 75 %

(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 TJ= 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)

Typ Limit (1)

SYSTEM PARAMETERS Figure 21 and Figure 22(2)

VOUT Output Voltage VIN = 12V, ILOAD = 0.5A 5.0 V

Circuit of Figure 21 and Figure 22 4.900 V(Min)

5.100 V(Max)

VOUT Output Voltage 0.5A ≤ILOAD ≤3A, 5.0 V

LM2576 8V ≤VIN ≤40V 4.800/4.750 V(Min)

Circuit of Figure 21 and Figure 22 5.200/5.250 V(Max)

VOUT Output Voltage 0.5A ≤ILOAD ≤3A, 5.0 V

LM2576HV 8V ≤VIN ≤60V 4.800/4.750 V(Min)

Circuit of Figure 21 and Figure 22 5.225/5.275 V(Max)

ηEfficiency VIN = 12V, ILOAD = 3A 77 %

(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 TJ= 25°C, and those with boldface type apply over full Operating Temperature

Range. LM2576-12 Units

LM2576HV-12

Symbol Parameter Conditions (Limits)

Typ Limit (1)

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

VOUT Output Voltage VIN = 25V, ILOAD = 0.5A 12 V

Circuit of Figure 21 and Figure 22 V(Min)

11.76

12.24 V(Max)

VOUT Output Voltage 0.5A ≤ILOAD ≤3A, 12 V

LM2576 15V ≤VIN ≤40V V(Min)

11.52/11.40

Circuit of Figure 21 and Figure 22 and 12.48/12.60 V(Max)

VOUT Output Voltage 0.5A ≤ILOAD ≤3A, 12 V

LM2576HV 15V ≤VIN ≤60V V(Min)

11.52/11.40

Circuit of Figure 21 and Figure 22 12.54/12.66 V(Max)

ηEfficiency VIN = 15V, ILOAD = 3A 88 %

(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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SNVS107C –JUNE 1999–REVISED APRIL 2013

ELECTRICAL CHARACTERISTICS LM2576-15, LM2576HV-15

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

Range. LM2576-15 Units

LM2576HV-15

Symbol Parameter Conditions (Limits)

Typ Limit (1)

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

VOUT Output Voltage VIN = 25V, ILOAD = 0.5A 15 V

Circuit of Figure 21 and Figure 22 14.70 V(Min)

15.30 V(Max)

VOUT Output Voltage 0.5A ≤ILOAD ≤3A, 15 V

LM2576 18V ≤VIN ≤40V 14.40/14.25 V(Min)

Circuit of Figure 21 and Figure 22 15.60/15.75 V(Max)

VOUT Output Voltage 0.5A ≤ILOAD ≤3A, 15 V

LM2576HV 18V ≤VIN ≤60V 14.40/14.25 V(Min)

Circuit of Figure 21 and Figure 22 15.68/15.83 V(Max)

ηEfficiency VIN = 18V, ILOAD = 3A 88 %

(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 TJ= 25°C, and those with boldface type apply over full Operating Temperature

Range. LM2576-ADJ Units

LM2576HV-ADJ

Symbol Parameter Conditions (Limits)

Typ Limit (1)

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

VOUT Feedback Voltage VIN = 12V, ILOAD = 0.5A 1.230 V

VOUT = 5V, 1.217 V(Min)

Circuit of Figure 21 and Figure 22 1.243 V(Max)

VOUT Feedback Voltage 0.5A ≤ILOAD ≤3A, 1.230 V

LM2576 8V ≤VIN ≤40V 1.193/1.180 V(Min)

VOUT = 5V, Circuit of Figure 21 and Figure 22 1.267/1.280 V(Max)

VOUT Feedback Voltage 0.5A ≤ILOAD ≤3A, 1.230 V

LM2576HV 8V ≤VIN ≤60V 1.193/1.180 V(Min)

VOUT = 5V, Circuit of Figure 21 and Figure 22 1.273/1.286 V(Max)

ηEfficiency VIN = 12V, ILOAD = 3A, VOUT = 5V 77 %

(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 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. ILOAD = 500 mA. LM2576-XX Units

LM2576HV-XX

Symbol Parameter Conditions (Limits)

Typ Limit (1)

DEVICE PARAMETERS

IbFeedback Bias Current VOUT = 5V (Adjustable Version Only) 50 100/500 nA

fOOscillator Frequency See (2) 52 kHz

47/42 kHz (Min)

58/63 kHz (Max)

VSAT Saturation Voltage IOUT = 3A (3) 1.4 V

1.8/2.0 V(Max)

DC Max Duty Cycle (ON) See (4) 98 %

93 %(Min)

ICL Current Limit See (3)(2) 5.8 A

4.2/3.5 A(Min)

6.9/7.5 A(Max)

ILOutput Leakage Current Output = 0V 2 mA(Max)

Output = −1V 7.5 mA

Output = −1V (5)(6) 30 mA(Max)

IQQuiescent Current See (5) 5 mA

10 mA(Max)

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

Current 200 μA(Max)

θJA Thermal Resistance T Package, Junction to Ambient (7) 65

θJA T Package, Junction to Ambient (8) 45 °C/W

θJC T Package, Junction to Case 2

θJA S Package, Junction to Ambient (9) 50

ON /OFF CONTROL Test Circuit Figure 21 and Figure 22

VIH ON /OFF Pin VOUT = 0V 1.4 2.2/2.4 V(Min)

Logic Input Level

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

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

Current 30 μA(Max)

IIL ON /OFF Pin = 0V (ON) 0 μA

10 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) VIN = 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, 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.

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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 Quiescent Current

Figure 6. Figure 7.

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TYPICAL PERFORMANCE CHARACTERISTICS (continued)

(Circuit of Figure 21 and Figure 22)Switch Saturation

Oscillator Frequency Voltage

Figure 8. Figure 9.

Efficiency Minimum Operating Voltage

Figure 10. Figure 11.

Quiescent Current Feedback Voltage

vs Duty Cycle vs Duty Cycle

Figure 12. Figure 13.

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TYPICAL PERFORMANCE CHARACTERISTICS (continued)

(Circuit of Figure 21 and Figure 22)Quiescent Current

Minimum Operating Voltage vs Duty Cycle

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

VOUT = 15V

If the DDPAK/TO-263 package is used, the thermal resistance can be A: Output Pin Voltage, 50V/div

reduced by increasing the PC board copper area thermally connected B: Output Pin Current, 2A/div

to the package. Using 0.5 square inches of copper area, θJA is C: Inductor Current, 2A/div

50°C/W, with 1 square inch of copper area, θJA is 37°C/W, and with D: Output Ripple Voltage, 50 mV/div,

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

CIN — 100 μF, 75V, Aluminum Electrolytic

COUT — 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

VREF = 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: Given:

VOUT = Regulated Output Voltage VOUT = 5V

(3.3V, 5V, 12V, or 15V) VIN(Max) = 15V

VIN(Max) = Maximum Input Voltage ILOAD(Max) = 3A

ILOAD(Max) = Maximum Load Current

1. Inductor Selection (L1) 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 B. From the selection guide, the inductance area intersected by the

or 15V respectively). For other output voltages, see the design 15V line and 3A line is L100.

procedure for the adjustable version. C. Inductor value required is 100 μH. From the table in Figure 23.

B. From the inductor value selection guide, identify the inductance Choose AIE 415-0930, Pulse Engineering PE92108, or Renco

region intersected by VIN(Max) and ILOAD(Max), and note the RL2444.

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 × ILOAD. For

additional inductor information, see INDUCTOR SELECTION.

2. Output Capacitor Selection (COUT) 2. Output Capacitor Selection (COUT)

A. The value of the output capacitor together with the inductor A. COUT = 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) 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 (CIN) 4. Input Capacitor (CIN)

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.

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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: Given:

VOUT = Regulated Output Voltage VOUT = 10V

VIN(Max) = Maximum Input Voltage VIN(Max) = 25V

ILOAD(Max) = Maximum Load Current ILOAD(Max) = 3A

F = Switching Frequency (Fixed at 52 kHz) 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 R2= 1k (8.13 −1) = 7.13k, closest 1% value is 7.15k

stability with time, use 1% metal film resistors)

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(For Continuous Mode Operation)

PROCEDURE (Adjustable Output Voltage Versions) EXAMPLE (Adjustable Output Voltage Versions)

2. Inductor Selection (L1) 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 C. ILOAD(Max) = 3A

the E • T number on the vertical axis of the Inductor Value D. Inductance Region = H150

Selection Guide shown in Figure 27.E. Inductor Value = 150 μHChoose from AIEpart #415-0936Pulse

C. On the horizontal axis, select the maximum load current. Engineering part #PE-531115, or Renco part #RL2445.

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 × ILOAD. For additional inductor

information, see INDUCTOR SELECTION.

3. Output Capacitor Selection (COUT) 3. Output Capacitor Selection (COUT)

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 However, for acceptable output ripple voltage select

requirement: COUT ≥680 μF

COUT = 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) 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 (CIN) 5. Input Capacitor (CIN)

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.

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

VR3A 4A–6A 3A 4A–6A

20V 1N5820 1N5823

MBR320P

SR302

30V 1N5821 50WQ03

MBR330 1N5824

31DQ03

SR303 The following

The following diodes are all

40V 1N5822 MBR340 diodes are all rated to 100V

MBR340 50WQ04 rated to 100V 50WF10

31DF1

31DQ04 1N5825 MUR410

HER302 HER602

SR304

50V MBR350 50WQ05

31DQ05

SR305

60V MBR360 50WR06

DQ06 50SQ060

SR306

Table 2. Inductor Selection by Manufacturer's Part Number

Inductor Code Inductor Value Schott (1) Pulse Eng. (2) Renco (3)

L47 47 μH 671 26980 PE-53112 RL2442

L68 68 μH 671 26990 PE-92114 RL2443

L100 100 μH 671 27000 PE-92108 RL2444

L150 150 μH 671 27010 PE-53113 RL1954

L220 220 μH 671 27020 PE-52626 RL1953

L330 330 μH 671 27030 PE-52627 RL1952

L470 470 μH 671 27040 PE-53114 RL1951

L680 680 μH 671 27050 PE-52629 RL1950

H150 150 μH 671 27060 PE-53115 RL2445

H220 220 μH 671 27070 PE-53116 RL2446

H330 330 μH 671 27080 PE-53117 RL2447

H470 470 μH 671 27090 PE-53118 RL1961

H680 680 μH 671 27100 PE-53119 RL1960

H1000 1000 μH 671 27110 PE-53120 RL1959

H1500 1500 μH 671 27120 PE-53121 RL1958

H2200 2200 μH 671 27130 PE-53122 RL2448

(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 (CIN)

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 (ΔIIND). 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 = (ΔIIND) (ESR of COUT) (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 0.03Ωcan 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 kΩbecause 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 +VIN without 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 θJA and θJC.

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

PD= (VIN)(IQ) + (VO/VIN)(ILOAD)(VSAT)

where

• IQ(quiescent current) and VSAT can be found in TYPICAL PERFORMANCE CHARACTERISTICS shown

previously,

• VIN is the applied minimum input voltage, VOis the regulated output voltage,

• and ILOAD is the load current. (3)

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:

ΔTJ= (PD) (θJA) (4)

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

temperature.

TJ=ΔTJ+ TA(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:

ΔTJ= (PD) (θJC +θinterface +θHeat sink) (6)

The operating junction temperature will be:

TJ= TA+ΔTJ(7)

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

• fosc = 52 kHz (8)

Under normal continuous inductor current operating conditions, the minimum VIN represents 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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LM2576-12

3 5

+1N5820

+COUT

2200 PF

Feedback

Output

VIN

CIN

100 PFGND

100 PH

VOUT = -12V

-VIN

-5V to -12V

LOW ESR

ON/OFF

LM2576, LM2576HV

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SNVS107C –JUNE 1999–REVISED APRIL 2013

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.

Typical Load Current

400 mA for VIN =−5.2V

750 mA for VIN =−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.

VTH ≈VZ1 + 2VBE(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 0.5Ωto

0.1ΩESR. 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 (ΔIIND). 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 (ISTBY)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 (ΔIIND)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•Top)The product (in VoIt•μs) of the voltage applied to the

inductor and the time the voltage is applied. This E•Top constant 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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Addendum-Page 1

PACKAGING INFORMATION

Orderable Device Status

(1)

Package Type Package

Drawing Pins Package

Qty Eco Plan

(2)

Lead/Ball Finish

(6)

MSL Peak Temp

(3)

Op Temp (°C) Device Marking

(4/5)

Samples

LM2576HVS-12 NRND DDPAK/

TO-263 KTT 5 45 TBD Call TI Call TI -40 to 125 LM2576

HVS-12 P+

LM2576HVS-12/NOPB ACTIVE DDPAK/

TO-263 KTT 5 45 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576

HVS-12 P+

LM2576HVS-3.3 NRND DDPAK/

TO-263 KTT 5 45 TBD Call TI Call TI -40 to 125 LM2576

HVS-3.3 P+

LM2576HVS-3.3/NOPB ACTIVE DDPAK/

TO-263 KTT 5 45 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576

HVS-3.3 P+

LM2576HVS-5.0 NRND DDPAK/

TO-263 KTT 5 45 TBD Call TI Call TI -40 to 125 LM2576

HVS-5.0 P+

LM2576HVS-5.0/NOPB ACTIVE DDPAK/

TO-263 KTT 5 45 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576

HVS-5.0 P+

LM2576HVS-ADJ NRND DDPAK/

TO-263 KTT 5 45 TBD Call TI Call TI -40 to 125 LM2576

HVS-ADJ P+

LM2576HVS-ADJ/NOPB ACTIVE DDPAK/

TO-263 KTT 5 45 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576

HVS-ADJ P+

LM2576HVSX-12 NRND DDPAK/

TO-263 KTT 5 500 TBD Call TI Call TI -40 to 125 LM2576

HVS-12 P+

LM2576HVSX-12/NOPB ACTIVE DDPAK/

TO-263 KTT 5 500 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576

HVS-12 P+

LM2576HVSX-3.3/NOPB ACTIVE DDPAK/

TO-263 KTT 5 500 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576

HVS-3.3 P+

LM2576HVSX-5.0 NRND DDPAK/

TO-263 KTT 5 500 TBD Call TI Call TI -40 to 125 LM2576

HVS-5.0 P+

LM2576HVSX-5.0/NOPB ACTIVE DDPAK/

TO-263 KTT 5 500 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576

HVS-5.0 P+

LM2576HVSX-ADJ NRND DDPAK/

TO-263 KTT 5 500 TBD Call TI Call TI -40 to 125 LM2576

HVS-ADJ P+

LM2576HVSX-ADJ/NOPB ACTIVE DDPAK/

TO-263 KTT 5 500 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576

HVS-ADJ P+

LM2576HVT-12 NRND TO-220 KC 5 45 TBD Call TI Call TI -40 to 125 LM2576HVT

-12 P+

LM2576HVT-12/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM LM2576HVT

-12 P+

PACKAGE OPTION ADDENDUM

www.ti.com 1-Nov-2013

Addendum-Page 2

Orderable Device Status

(1)

Package Type Package

Drawing Pins Package

Qty Eco Plan

(2)

Lead/Ball Finish

(6)

MSL Peak Temp

(3)

Op Temp (°C) Device Marking

(4/5)

Samples

LM2576HVT-12/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM -40 to 125 LM2576HVT

-12 P+

LM2576HVT-15 NRND TO-220 KC 5 45 TBD Call TI Call TI -40 to 125 LM2576HVT

-15 P+

LM2576HVT-15/LB03 NRND TO-220 NDH 5 45 TBD Call TI Call TI LM2576HVT

-15 P+

LM2576HVT-15/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM LM2576HVT

-15 P+

LM2576HVT-15/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM -40 to 125 LM2576HVT

-15 P+

LM2576HVT-5.0 NRND TO-220 KC 5 45 TBD Call TI Call TI -40 to 125 LM2576HVT

-5.0 P+

LM2576HVT-5.0/LB03 NRND TO-220 NDH 5 45 TBD Call TI Call TI LM2576HVT

-5.0 P+

LM2576HVT-5.0/LF02 ACTIVE TO-220 NEB 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM LM2576HVT

-5.0 P+

LM2576HVT-5.0/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM LM2576HVT

-5.0 P+

LM2576HVT-5.0/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM -40 to 125 LM2576HVT

-5.0 P+

LM2576HVT-ADJ NRND TO-220 KC 5 45 TBD Call TI Call TI -40 to 125 LM2576HVT

-ADJ P+

LM2576HVT-ADJ/LB03 NRND TO-220 NDH 5 45 TBD Call TI Call TI LM2576HVT

-ADJ P+

LM2576HVT-ADJ/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM LM2576HVT

-ADJ P+

LM2576HVT-ADJ/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM -40 to 125 LM2576HVT

-ADJ P+

LM2576S-12 NRND DDPAK/

TO-263 KTT 5 45 TBD Call TI Call TI -40 to 125 LM2576S

-12 P+

LM2576S-12/NOPB ACTIVE DDPAK/

TO-263 KTT 5 45 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576S

-12 P+

LM2576S-3.3/NOPB ACTIVE DDPAK/

TO-263 KTT 5 45 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576S

-3.3 P+

LM2576S-5.0 NRND DDPAK/

TO-263 KTT 5 45 TBD Call TI Call TI -40 to 125 LM2576S

-5.0 P+

PACKAGE OPTION ADDENDUM

www.ti.com 1-Nov-2013

Addendum-Page 3

Orderable Device Status

(1)

Package Type Package

Drawing Pins Package

Qty Eco Plan

(2)

Lead/Ball Finish

(6)

MSL Peak Temp

(3)

Op Temp (°C) Device Marking

(4/5)

Samples

LM2576S-5.0/NOPB ACTIVE DDPAK/

TO-263 KTT 5 45 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576S

-5.0 P+

LM2576S-ADJ ACTIVE DDPAK/

TO-263 KTT 5 TBD Call TI Call TI -40 to 125 LM2576S

-ADJ P+

LM2576S-ADJ/NOPB ACTIVE DDPAK/

TO-263 KTT 5 45 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576S

-ADJ P+

LM2576SX-3.3/NOPB ACTIVE DDPAK/

TO-263 KTT 5 500 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576S

-3.3 P+

LM2576SX-5.0/NOPB ACTIVE DDPAK/

TO-263 KTT 5 500 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576S

-5.0 P+

LM2576SX-ADJ/NOPB ACTIVE DDPAK/

TO-263 KTT 5 500 Pb-Free (RoHS

Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2576S

-ADJ P+

LM2576T-12 NRND TO-220 KC 5 45 TBD Call TI Call TI -40 to 125 LM2576T

-12 P+

LM2576T-12/LB03 NRND TO-220 NDH 5 45 TBD Call TI Call TI LM2576T

-12 P+

LM2576T-12/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM LM2576T

-12 P+

LM2576T-12/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM -40 to 125 LM2576T

-12 P+

LM2576T-15/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM LM2576T

-15 P+

LM2576T-15/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM -40 to 125 LM2576T

-15 P+

LM2576T-3.3/LB03 NRND TO-220 NDH 5 45 TBD Call TI Call TI LM2576T

-3.3 P+

LM2576T-3.3/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM LM2576T

-3.3 P+

LM2576T-3.3/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM -40 to 125 LM2576T

-3.3 P+

LM2576T-5.0 NRND TO-220 KC 5 45 TBD Call TI Call TI -40 to 125 LM2576T

-5.0 P+

LM2576T-5.0/LB03 NRND TO-220 NDH 5 45 TBD Call TI Call TI LM2576T

-5.0 P+

LM2576T-5.0/LF02 ACTIVE TO-220 NEB 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM LM2576T

-5.0 P+

PACKAGE OPTION ADDENDUM

www.ti.com 1-Nov-2013

Addendum-Page 4

Orderable Device Status

(1)

Package Type Package

Drawing Pins Package

Qty Eco Plan

(2)

Lead/Ball Finish

(6)

MSL Peak Temp

(3)

Op Temp (°C) Device Marking

(4/5)

Samples

LM2576T-5.0/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM LM2576T

-5.0 P+

LM2576T-5.0/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM -40 to 125 LM2576T

-5.0 P+

LM2576T-ADJ NRND TO-220 KC 5 45 TBD Call TI Call TI -40 to 125 LM2576T

-ADJ P+

LM2576T-ADJ/LB03 NRND TO-220 NDH 5 45 TBD Call TI Call TI LM2576T

-ADJ P+

LM2576T-ADJ/LF02 ACTIVE TO-220 NEB 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM LM2576T

-ADJ P+

LM2576T-ADJ/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM LM2576T

-ADJ P+

LM2576T-ADJ/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS

& no Sb/Br) CU SN Level-1-NA-UNLIM -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.

PACKAGE OPTION ADDENDUM

www.ti.com 1-Nov-2013

Addendum-Page 5

(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.

TAPE AND REEL INFORMATION

*All dimensions are nominal

Device Package

Type Package

Drawing Pins SPQ Reel

Diameter

(mm)

Reel

Width

W1 (mm)

(mm) B0

(mm) K0

(mm) P1

(mm) W

(mm) Pin1

Quadrant

LM2576HVSX-12 DDPAK/

TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2

LM2576HVSX-12/NOPB DDPAK/

TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2

LM2576HVSX-3.3/NOPB DDPAK/

TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2

LM2576HVSX-5.0 DDPAK/

TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2

LM2576HVSX-5.0/NOPB DDPAK/

TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2

LM2576HVSX-ADJ DDPAK/

TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2

LM2576HVSX-ADJ/NOPB DDPAK/

TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2

LM2576SX-3.3/NOPB DDPAK/

TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2

LM2576SX-5.0/NOPB DDPAK/

TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2

LM2576SX-ADJ/NOPB DDPAK/

TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2

PACKAGE MATERIALS INFORMATION

www.ti.com 23-Sep-2013

Pack Materials-Page 1

*All dimensions are nominal

Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)

LM2576HVSX-12 DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0

LM2576HVSX-12/NOPB DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0

LM2576HVSX-3.3/NOPB DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0

LM2576HVSX-5.0 DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0

LM2576HVSX-5.0/NOPB DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0

LM2576HVSX-ADJ DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0

LM2576HVSX-ADJ/NOPB DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0

LM2576SX-3.3/NOPB DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0

LM2576SX-5.0/NOPB DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0

LM2576SX-ADJ/NOPB DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0

PACKAGE MATERIALS INFORMATION

www.ti.com 23-Sep-2013

Pack Materials-Page 2

MECHANICAL DATA

NDH0005D

www.ti.com

MECHANICAL DATA

KTT0005B

www.ti.com

BOTTOM SIDE OF PACKAGE

TS5B (Rev D)

MECHANICAL DATA

NEB0005B

www.ti.com

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