TI LM2576T-12

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.
1
23
•
•
•
•
•
•
•
•
•
•
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
Requires Only 4 External Components
52 kHz Fixed Frequency Internal Oscillator
TTL Shutdown Capability, Low Power Standby
Mode
High Efficiency
Uses Readily Available Standard Inductors
Thermal Shutdown and Current Limit
Protection
P+ Product Enhancement Tested
APPLICATIONS
•
•
•
•
Simple High-Efficiency Step-Down (Buck)
Regulator
Efficient Pre-Regulator for Linear Regulators
On-Card Switching Regulators
Positive to Negative Converter (Buck-Boost)
Requiring a minimum number of external
components, these regulators are simple to use and
include internal frequency compensation and a fixedfrequency oscillator.
The LM2576 series offers a high-efficiency
replacement for popular three-terminal linear
regulators. It substantially reduces the size of the
heat sink, and in some cases no heat sink is
required.
A standard series of inductors optimized for use with
the LM2576 are available from several different
manufacturers. This feature greatly simplifies the
design of switch-mode power supplies.
Other features include a 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.
TYPICAL APPLICATION
(Fixed Output Voltage Versions)
Figure 1.
1
2
3
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.
Copyright © 1999–2013, Texas Instruments Incorporated
LM2576, LM2576HV
SNVS107C – JUNE 1999 – REVISED APRIL 2013
www.ti.com
Block Diagram
3.3V R2 = 1.7k
5V, R2 = 3.1k
12V, R2 = 8.84k
15V, R2 = 11.3k
For ADJ. Version
R1 = Open, R2 = 0Ω
Patent Pending
2
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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
−0.3V ≤ V ≤ +VIN
ON /OFF Pin Input Voltage
Output Voltage to Ground
−1V
(Steady State)
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)
Lead Temperature
(Soldering, 10 Seconds)
(1)
(2)
2 kV
260°C
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.
If Military/Aerospace specified devices are required, please contact the TI Sales Office/ Distributors for availability and specifications.
OPERATING RATINGS
−40°C ≤ TJ ≤ +125°C
Temperature Range
LM2576/LM2576HV
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.
Symbol
Parameter
LM2576-3.3
LM2576HV-3.3
Conditions
Typ
Limit
(1)
Units
(Limits)
SYSTEM PARAMETERS Test Circuit Figure 21 and Figure 22 (2)
VOUT
VOUT
VOUT
η
(1)
(2)
Output Voltage
VIN = 12V, ILOAD = 0.5A
Circuit of Figure 21 and Figure 22
3.3
Output Voltage
LM2576
6V ≤ VIN ≤ 40V, 0.5A ≤ ILOAD ≤ 3A
Circuit of Figure 21 and Figure 22
3.3
Output Voltage
LM2576HV
6V ≤ VIN ≤ 60V, 0.5A ≤ ILOAD ≤ 3A
Circuit of Figure 21 and Figure 22
3.3
Efficiency
VIN = 12V, ILOAD = 3A
75
3.234
3.366
V
V(Min)
V(Max)
3.168/3.135
3.432/3.465
V
V(Min)
V(Max)
3.168/3.135
3.450/3.482
V
V(Min)
V(Max)
%
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.
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.
Symbol
Parameter
LM2576-5.0
LM2576HV-5.0
Conditions
Typ
Limit
(1)
Units
(Limits)
SYSTEM PARAMETERS Figure 21 and Figure 22 (2)
VOUT
Output Voltage
VOUT
VOUT
η
(1)
(2)
VIN = 12V, ILOAD = 0.5A
Circuit of Figure 21 and Figure 22
5.0
Output Voltage
LM2576
0.5A ≤ ILOAD ≤ 3A,
8V ≤ VIN ≤ 40V
Circuit of Figure 21 and Figure 22
5.0
Output Voltage
LM2576HV
0.5A ≤ ILOAD ≤ 3A,
8V ≤ VIN ≤ 60V
Circuit of Figure 21 and Figure 22
5.0
Efficiency
VIN = 12V, ILOAD = 3A
77
4.900
5.100
V
V(Min)
V(Max)
4.800/4.750
5.200/5.250
V
V(Min)
V(Max)
4.800/4.750
5.225/5.275
V
V(Min)
V(Max)
%
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.
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.
Symbol
Parameter
LM2576-12
LM2576HV-12
Conditions
Typ
Limit
(1)
Units
(Limits)
SYSTEM PARAMETERS Test Circuit Figure 21 and Figure 22 (2)
VOUT
Output Voltage
VIN = 25V, ILOAD = 0.5A
Circuit of Figure 21 and Figure 22
12
V
11.76
12.24
VOUT
VOUT
η
(1)
(2)
4
Output Voltage
LM2576
Output Voltage
LM2576HV
Efficiency
0.5A ≤ ILOAD ≤ 3A,
15V ≤ VIN ≤ 40V
Circuit of Figure 21 and Figure 22 and
12
12
88
V(Min)
V(Max)
V
11.52/11.40
12.54/12.66
VIN = 15V, ILOAD = 3A
V(Max)
V
11.52/11.40
12.48/12.60
0.5A ≤ ILOAD ≤ 3A,
15V ≤ VIN ≤ 60V
Circuit of Figure 21 and Figure 22
V(Min)
V(Min)
V(Max)
%
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.
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 TJ = 25°C, and those with boldface type apply over full Operating Temperature
Range.
Symbol
Parameter
LM2576-15
LM2576HV-15
Conditions
Typ
Limit
Units
(Limits)
(1)
SYSTEM PARAMETERS Test Circuit Figure 21 and Figure 22 (2)
VOUT
VOUT
VOUT
η
(1)
(2)
Output Voltage
VIN = 25V, ILOAD = 0.5A
Circuit of Figure 21 and Figure 22
15
Output Voltage
LM2576
0.5A ≤ ILOAD ≤ 3A,
18V ≤ VIN ≤ 40V
Circuit of Figure 21 and Figure 22
15
Output Voltage
LM2576HV
0.5A ≤ ILOAD ≤ 3A,
18V ≤ VIN ≤ 60V
Circuit of Figure 21 and Figure 22
15
Efficiency
VIN = 18V, ILOAD = 3A
88
14.70
15.30
V
V(Min)
V(Max)
14.40/14.25
15.60/15.75
V
V(Min)
V(Max)
14.40/14.25
15.68/15.83
V
V(Min)
V(Max)
%
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.
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.
Symbol
Parameter
Conditions
LM2576-ADJ
LM2576HV-ADJ
Typ
Limit
(1)
Units
(Limits)
SYSTEM PARAMETERS Test Circuit Figure 21 and Figure 22 (2)
VOUT
VOUT
VOUT
η
(1)
(2)
Feedback Voltage
VIN = 12V, ILOAD = 0.5A
VOUT = 5V,
Circuit of Figure 21 and Figure 22
1.230
Feedback Voltage
LM2576
0.5A ≤ ILOAD ≤ 3A,
8V ≤ VIN ≤ 40V
VOUT = 5V, Circuit of Figure 21 and Figure 22
1.230
Feedback Voltage
LM2576HV
0.5A ≤ ILOAD ≤ 3A,
8V ≤ VIN ≤ 60V
VOUT = 5V, Circuit of Figure 21 and Figure 22
1.230
Efficiency
VIN = 12V, ILOAD = 3A, VOUT = 5V
1.217
1.243
V
V(Min)
V(Max)
1.193/1.180
1.267/1.280
V
V(Min)
V(Max)
1.193/1.180
1.273/1.286
V
V(Min)
V(Max)
77
%
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.
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.
Symbol
Parameter
LM2576-XX
LM2576HV-XX
Conditions
Typ
Limit
(1)
Units
(Limits)
DEVICE PARAMETERS
Ib
Feedback Bias Current
VOUT = 5V (Adjustable Version Only)
fO
Oscillator Frequency
See
VSAT
DC
Max Duty Cycle (ON)
ICL
Current Limit
IL
Output Leakage Current
IQ
Quiescent Current
ISTBY
θJA
θJA
θJC
θJA
Saturation Voltage
IOUT = 3A
See
See
100/500
nA
47/42
58/63
kHz
kHz (Min)
kHz (Max)
1.8/2.0
V
V(Max)
93
%
%(Min)
4.2/3.5
6.9/7.5
A
A(Min)
A(Max)
52
(3)
1.4
(4)
98
(3) (2)
Output = 0V
Output = −1V
Output = −1V
See
50
(2)
5.8
2
(5) (6)
(5)
Standby Quiescent
Current
ON /OFF Pin = 5V (OFF)
Thermal Resistance
T Package, Junction to Ambient
T Package, Junction to Ambient
T Package, Junction to Case
S Package, Junction to Ambient
30
mA(Max)
mA
mA(Max)
10
mA
mA(Max)
200
μA
μA(Max)
7.5
5
50
(7)
(8)
65
45
2
50
(9)
°C/W
ON /OFF CONTROL Test Circuit Figure 21 and Figure 22
VIH
VIL
IIH
ON /OFF Pin
Logic Input Level
VOUT = 0V
1.4
2.2/2.4
V(Min)
VOUT = Nominal Output Voltage
1.2
1.0/0.8
V(Max)
ON /OFF Pin Input
Current
ON /OFF Pin = 5V (OFF)
12
30
μA
μA(Max)
10
μA
μA(Max)
IIL
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
6
ON /OFF Pin = 0V (ON)
0
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.
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%.
Output pin sourcing current. No diode, inductor or capacitor connected to output.
Feedback pin removed from output and connected to 0V.
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.
VIN = 40V (60V for high voltage version).
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.
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.
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.
Quiescent Current
Standby
Quiescent Current
Figure 6.
Figure 7.
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TYPICAL PERFORMANCE CHARACTERISTICS (continued)
(Circuit of Figure 21 and Figure 22)
8
Oscillator Frequency
Switch Saturation
Voltage
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)
Minimum Operating Voltage
Quiescent Current
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
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.
Figure 18.
VOUT = 15V
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 19.
Load Transient Response
Figure 20.
10
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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:
VOUT = Regulated Output Voltage
(3.3V, 5V, 12V, or 15V)
VIN(Max) = Maximum Input Voltage
ILOAD(Max) = Maximum Load Current
Given:
VOUT = 5V
VIN(Max) = 15V
ILOAD(Max) = 3A
1. Inductor Selection (L1)
A. Select the correct Inductor value selection guide from Figure 23,
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 inductor value selection guide, identify the inductance
region intersected by VIN(Max) and ILOAD(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 × ILOAD. For
additional inductor information, see INDUCTOR SELECTION.
1. Inductor Selection (L1)
A. Use the selection guide shown in Figure 24.
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.
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)
A.The catch-diode current rating must be at least 1.2 times greater
than the maximum load current. Also, if the power supply design
must withstand a continuous output short, the diode should have a
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.
3. Catch Diode Selection (D1)
A.For this example, a 3A current rating is adequate.
B. Use a 20V 1N5823 or SR302 Schottky diode, or any of the
suggested fast-recovery diodes shown in Table 1.
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.
12
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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)
Given:
VOUT = Regulated Output Voltage
VIN(Max) = Maximum Input Voltage
ILOAD(Max) = Maximum Load Current
F = Switching Frequency (Fixed at 52 kHz)
EXAMPLE (Adjustable Output Voltage Versions)
Given:
VOUT = 10V
VIN(Max) = 25V
ILOAD(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.
R1 can 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)
14
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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. 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. 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 × ILOAD. For additional inductor
information, see INDUCTOR SELECTION.
B. E • T = 115 V • μs
C. ILOAD(Max) = 3A
D. Inductance Region = H150
E. Inductor Value = 150 μH Choose from AIEpart #415-0936Pulse
Engineering part #PE-531115, or Renco part #RL2445.
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)
A. The catch-diode current rating must be at least 1.2 times greater
than the maximum load current. Also, if the power supply design
must withstand a continuous output short, the diode should have a
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.
4. Catch Diode Selection (D1)
A. For this example, a 3.3A current rating is adequate.
B. Use a 30V 31DQ03 Schottky diode, or any of the suggested fastrecovery diodes in Table 1.
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
VR
20V
3A
Fast Recovery
4A–6A
1N5820
3A
4A–6A
The following
diodes are all
rated to 100V
31DF1
HER302
The following
diodes are all
rated to 100V
50WF10
MUR410
HER602
1N5823
MBR320P
SR302
30V
1N5821
50WQ03
MBR330
1N5824
31DQ03
SR303
40V
1N5822
MBR340
MBR340
50WQ04
31DQ04
1N5825
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)
(2)
(3)
16
Schott Corporation, (612) 475-1173, 1000 Parkers Lake Road, Wayzata, MN 55391.
Pulse Engineering, (619) 674-8100, P.O. Box 12235, San Diego, CA 92112.
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 0.03Ω 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 +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, VO is 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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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
VIN
LM2576-12
1
+
4
Output
LOW ESR
2
+
3
GND
CIN
5
ON/OFF
COUT
2200 PF
1N5820
100 PF
VOUT = -12V
100 PH
-VIN
-5V to -12V
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 REGULATOR A switching regulator topology in which a higher voltage is converted to a lower voltage.
Also known as a step-down switching regulator.
BUCK-BOOST REGULATOR A 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 DIODE The 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 VOLTAGE The 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-topeak value of this sawtooth ripple current can be determined by reading the INDUCTOR RIPPLE
CURRENT section.
CAPACITOR RIPPLE CURRENT RMS 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 OPERATION Relates 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 SATURATION The 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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4-Jun-2013
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
(2)
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
LM2576HVS-12
ACTIVE
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
ACTIVE
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
ACTIVE
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
ACTIVE
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
ACTIVE
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
ACTIVE
DDPAK/
TO-263
KTT
5
500
TBD
Call TI
Call TI
-40 to 125
LM2576
HVS-3.3 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
ACTIVE
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
ACTIVE
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
ACTIVE
TO-220
KC
5
45
TBD
Call TI
Call TI
-40 to 125
LM2576HVT
-12 P+
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
4-Jun-2013
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
(2)
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
LM2576HVT-12/LF03
ACTIVE
TO-220
NDH
5
45
Green (RoHS
& no Sb/Br)
CU SN
Level-1-NA-UNLIM
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
ACTIVE
TO-220
KC
5
45
TBD
Call TI
Call TI
-40 to 125
LM2576HVT
-15 P+
LM2576HVT-15/LB03
ACTIVE
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
ACTIVE
TO-220
KC
5
45
TBD
Call TI
Call TI
-40 to 125
LM2576HVT
-5.0 P+
LM2576HVT-5.0/LB03
ACTIVE
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
ACTIVE
TO-220
KC
5
45
TBD
Call TI
Call TI
-40 to 125
LM2576HVT
-ADJ P+
LM2576HVT-ADJ/LB03
ACTIVE
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
ACTIVE
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
ACTIVE
DDPAK/
TO-263
KTT
5
45
TBD
Call TI
Call TI
-40 to 125
LM2576S
-3.3 P+
Addendum-Page 2
LM2576HVT
-12 P+
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
4-Jun-2013
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
(2)
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
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
ACTIVE
DDPAK/
TO-263
KTT
5
45
TBD
Call TI
Call TI
-40 to 125
LM2576S
-5.0 P+
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
ACTIVE
DDPAK/
TO-263
KTT
5
500
TBD
Call TI
Call TI
-40 to 125
LM2576S
-3.3 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
ACTIVE
TO-220
KC
5
45
TBD
Call TI
Call TI
-40 to 125
LM2576T
-12 P+
LM2576T-12/LB03
ACTIVE
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
ACTIVE
TO-220
KC
5
45
TBD
Call TI
Call TI
-40 to 125
LM2576T
-15 P+
LM2576T-15/LF03
ACTIVE
TO-220
NDH
5
45
Green (RoHS
& no Sb/Br)
CU SN
Level-1-NA-UNLIM
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
ACTIVE
TO-220
KC
5
45
TBD
Call TI
Call TI
-40 to 125
LM2576T
-3.3 P+
LM2576T-3.3/LB03
ACTIVE
TO-220
NDH
5
45
TBD
Call TI
Call TI
Addendum-Page 3
LM2576T
-15 P+
LM2576T
-3.3 P+
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
4-Jun-2013
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
(2)
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
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
ACTIVE
TO-220
KC
5
45
TBD
Call TI
Call TI
-40 to 125
LM2576T
-5.0 P+
LM2576T-5.0/LB03
ACTIVE
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+
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
ACTIVE
TO-220
KC
5
45
TBD
Call TI
Call TI
-40 to 125
LM2576T
-ADJ P+
LM2576T-ADJ/LB03
ACTIVE
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.
Addendum-Page 4
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
4-Jun-2013
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.
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
8-Apr-2013
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) 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
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
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
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
LM2576HVSX-5.0
LM2576HVSX-ADJ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
LM2576SX-3.3
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/
KTT
5
500
330.0
24.4
10.75
14.85
5.0
16.0
24.0
Q2
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
8-Apr-2013
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
14.85
5.0
16.0
24.0
TO-263
LM2576SX-ADJ/NOPB
DDPAK/
TO-263
KTT
5
500
330.0
24.4
10.75
Q2
*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
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
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
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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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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Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements
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In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is to
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No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties
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