LM1575/LM2575/LM2575HV
LM1575/LM2575/LM2575HV
SIMPLE SWITCHER ® 1A Step-Down Voltage Regulator
General Description
Features
The LM2575 series of regulators are monolithic integrated
circuits that provide all the active functions for a step-down
(buck) switching regulator, capable of driving a 1A load with
excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5V, 12V, 15V, and an
adjustable output version.
n 3.3V, 5V, 12V, 15V, and adjustable output versions
n Adjustable version output voltage range,
1.23V to 37V (57V for HV version) ± 4% max over
line and load conditions
n Guaranteed 1A output current
n Wide input voltage range, 40V up to 60V for HV version
n Requires only 4 external components
n 52 kHz fixed frequency internal oscillator
n TTL shutdown capability, low power standby mode
n High efficiency
n Uses readily available standard inductors
n Thermal shutdown and current limit protection
n P+ Product Enhancement tested
Requiring a minimum number of external components, these
regulators are simple to use and include internal frequency
compensation and a fixed-frequency oscillator.
The LM2575 series offers a high-efficiency replacement for
popular three-terminal linear regulators. It substantially reduces the size of the heat sink, and in many cases no heat
sink is required.
A standard series of inductors optimized for use with the
LM2575 are available from several different manufacturers.
This feature greatly simplifies the design of switch-mode
power supplies.
Other features include a guaranteed ± 4% tolerance on output voltage within specified input voltages and output load
conditions, and ± 10% on the oscillator frequency. External
shutdown is included, featuring 50 µA (typical) standby current.
Typical Application
Applications
n
n
n
n
Simple high-efficiency step-down (buck) regulator
Efficient pre-regulator for linear regulators
On-card switching regulators
Positive to negative converter (Buck-Boost)
(Fixed Output Voltage
Versions)
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2018 NOV
LM1575/LM2575/LM2575HV
Block Diagram and Typical Application
3.3V, R2 = 1.7k
5V, R2 = 3.1k
12V, R2 = 8.84k
15V, R2 = 11.3k
For ADJ. Version
R1 = Open, R2 = 0Ω
Note: Pin numbers are for the TO-220 package.
FIGURE 1.
Connection Diagrams
(XXindicatesoutputvoltageoption.)
Straight Leads
5–Lead TO-220 (T)
Bent, Staggered Leads
5-Lead TO-220 (T)
Top View
LM2575T-XX or LM2575HVT-XX
Top View
TO-263(S)
5-Lead Surface-Mount Package
Side View
LM2575T-XX Flow LB03 or
LM2575HVT-XX Flow LB03
Top View
Side View
LM2575S-XX or LM2575HVS-XX
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2018 NOV
LM1575/LM2575/LM2575HV
Absolute Maximum Ratings
(Note 1)
Maximum Supply Voltage
LM1575/LM2575
45V
LM2575HV
63V
ON /OFF Pin Input Voltage
Lead Temperature
(Soldering, 10 sec.)
260˚C
Operating Ratings
−0.3V ≤ V ≤ +VIN
Output Voltage to Ground
Temperature Range
(Steady State)
−1V
Power Dissipation
Internally Limited
Storage Temperature Range
−65˚C to +150˚C
Maximum Junction Temperature
−55˚C ≤ TJ ≤ +150˚C
−40˚C ≤ TJ ≤ +125˚C
Supply Voltage
150˚C
Minimum ESD Rating
(C = 100 pF, R = 1.5 kΩ)
LM1575
LM2575/LM2575HV
LM1575/LM2575
40V
LM2575HV
60V
2 kV
LM1575-3.3, LM2575-3.3, LM2575HV-3.3
Electrical Characteristics
Specifications with standard type face are for TJ = 25˚C, and those with boldface type apply over full Operating Temperature Range .
Symbol
Parameter
Conditions
Typ
LM1575-3.3
LM2575-3.3
LM2575HV-3.3
Units
(Limits)
Limit
Limit
(Note 2)
(Note 3)
3.267
3.234
V(Min)
3.333
3.366
V(Max)
3.200/3.168
3.168/3.135
V(Min)
3.400/3.432
3.432/3.465
V(Max)
3.200/3.168
3.168/3.135
V(Min)
3.416/3.450
3.450/3.482
V(Max)
SYSTEM PARAMETERS (Note 4) Test Circuit Figure 2
VOUT
Output Voltage
VIN = 12V, ILOAD = 0.2A
3.3
V
Circuit of Figure 2
VOUT
VOUT
η
Output Voltage
4.75V ≤ VIN ≤ 40V, 0.2A ≤ ILOAD ≤ 1A
LM1575/LM2575
Circuit of Figure 2
Output Voltage
4.75V ≤ VIN ≤ 60V, 0.2A ≤ ILOAD ≤ 1A
LM2575HV
Circuit of Figure 2
Efficiency
VIN = 12V, ILOAD = 1A
3.3
V
3.3
V
75
%
LM1575-5.0, LM2575-5.0, LM2575HV-5.0
Electrical Characteristics
Specifications with standard type face are for TJ = 25˚C, and those with boldface type apply over full Operating Temperature Range.
Symbol
Parameter
Conditions
Typ
LM1575-5.0
LM2575-5.0
LM2575HV-5.0
Units
(Limits)
Limit
Limit
(Note 2)
(Note 3)
4.950
4.900
V(Min)
5.050
5.100
V(Max)
4.850/4.800
4.800/4.750
V(Min)
5.150/5.200
5.200/5.250
V(Max)
SYSTEM PARAMETERS (Note 4) Test Circuit Figure 2
VOUT
Output Voltage
VIN = 12V, ILOAD = 0.2A
5.0
Circuit of Figure 2
VOUT
Output Voltage
0.2A ≤ ILOAD ≤ 1A,
LM1575/LM2575
8V ≤ VIN ≤ 40V
Output Voltage
0.2A ≤ ILOAD ≤ 1A,
LM2575HV
8V ≤ VIN ≤ 60V
4.850/4.800
4.800/4.750
V(Min)
Circuit of Figure 2
5.175/5.225
5.225/5.275
V(Max)
5.0
Circuit of Figure 2
VOUT
V
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V
5.0
3
V
2018 NOV
LM1575/LM2575/LM2575HV
LM1575-5.0, LM2575-5.0, LM2575HV-5.0
Electrical Characteristics (Continued)
Specifications with standard type face are for TJ = 25˚C, and those with boldface type apply over full Operating Temperature Range.
Symbol
Parameter
Conditions
Typ
LM1575-5.0
LM2575-5.0
LM2575HV-5.0
η
Efficiency
VIN = 12V, ILOAD = 1A
Limit
Limit
(Note 2)
(Note 3)
77
Units
(Limits)
%
LM1575-12, LM2575-12, LM2575HV-12
Electrical Characteristics
Specifications with standard type face are for TJ = 25˚C, and those with boldface type apply over full Operating Temperature Range .
Symbol
Parameter
Conditions
Typ
LM1575-12
LM2575-12
LM2575HV-12
Units
(Limits)
Limit
Limit
(Note 2)
(Note 3)
11.88
11.76
V(Min)
12.12
12.24
V(Max)
11.64/11.52
11.52/11.40
V(Min)
12.36/12.48
12.48/12.60
V(Max)
11.64/11.52
11.52/11.40
V(Min)
12.42/12.54
12.54/12.66
V(Max)
SYSTEM PARAMETERS (Note 4) Test Circuit Figure 2
VOUT
Output Voltage
VIN = 25V, ILOAD = 0.2A
12
Circuit of Figure 2
VOUT
Output Voltage
0.2A ≤ ILOAD ≤ 1A,
LM1575/LM2575
15V ≤ VIN ≤ 40V
Output Voltage
0.2A ≤ ILOAD ≤ 1A,
LM2575HV
15V ≤ VIN ≤ 60V
Efficiency
VIN = 15V, ILOAD = 1A
12
Circuit of Figure 2
VOUT
V
12
Circuit of Figure 2
η
V
V
88
%
LM1575-15, LM2575-15, LM2575HV-15
Electrical Characteristics
Specifications with standard type face are for TJ = 25˚C, and those with boldface type apply over full Operating Temperature Range .
Symbol
Parameter
Conditions
Typ
LM1575-15
LM2575-15
LM2575HV-15
Units
(Limits)
Limit
Limit
(Note 2)
(Note 3)
14.85
14.70
V(Min)
15.15
15.30
V(Max)
SYSTEM PARAMETERS (Note 4) Test Circuit Figure 2
VOUT
Output Voltage
VIN = 30V, ILOAD = 0.2A
15
Circuit of Figure 2
VOUT
VOUT
Output Voltage
0.2A ≤ ILOAD ≤ 1A,
LM1575/LM2575
18V ≤ VIN ≤ 40V
14.55/14.40
14.40/14.25
V(Min)
Circuit of Figure 2
15.45/15.60
15.60/15.75
V(Max)
14.55/14.40
14.40/14.25
V(Min)
15.525/15.675
15.68/15.83
V(Max)
Output Voltage
0.2A ≤ ILOAD ≤ 1A,
LM2575HV
18V ≤ VIN ≤ 60V
15
Efficiency
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V
15
Circuit of Figure 2
η
V
VIN = 18V, ILOAD = 1A
88
4
V
%
2018 NOV
LM1575/LM2575/LM2575HV
LM1575-ADJ, LM2575-ADJ, LM2575HV-ADJ
Electrical Characteristics
Specifications with standard type face are for TJ= 25˚C, and those with boldface type apply over full Operating Temperature
Range.
Symbol
Parameter
Conditions
Typ
LM1575-ADJ
LM2575-ADJ
Units
LM2575HV-ADJ (Limits)
Limit
Limit
(Note 2)
(Note 3)
SYSTEM PARAMETERS (Note 4) Test Circuit Figure 2
VOUT
VOUT
VOUT
η
Feedback Voltage
VIN = 12V, ILOAD = 0.2A
1.230
V
VOUT = 5V
1.217
1.217
V(Min)
Circuit of Figure 2
1.243
1.243
V(Max)
Feedback Voltage
0.2A ≤ ILOAD ≤ 1A,
LM1575/LM2575
8V ≤ VIN ≤ 40V
1.205/1.193
1.193/1.180
V(Min)
VOUT = 5V, Circuit of Figure 2
1.255/1.267
1.267/1.280
V(Max)
1.230
V
Feedback Voltage
0.2A ≤ ILOAD ≤ 1A,
LM2575HV
8V ≤ VIN ≤ 60V
1.205/1.193
1.193/1.180
V(Min)
VOUT = 5V, Circuit of Figure 2
1.261/1.273
1.273/1.286
V(Max)
Efficiency
1.230
VIN = 12V, ILOAD = 1A, VOUT = 5V
V
77
%
All Output Voltage Versions
Electrical Characteristics
Specifications with standard type face are for TJ = 25˚C, and those with boldface type apply over full Operating Temperature Range. Unless otherwise specified, VIN = 12V for the 3.3V, 5V, and Adjustable version, VIN = 25V for the 12V version,
and VIN = 30V for the 15V version. ILOAD = 200 mA.
Symbol
Parameter
Conditions
Typ
LM1575-XX
LM2575-XX
Units
LM2575HV-XX (Limits)
Limit
Limit
(Note 2)
(Note 3)
100/500
100/500
DEVICE PARAMETERS
Ib
Feedback Bias Current
VOUT = 5V (Adjustable Version Only)
50
fO
Oscillator Frequency
(Note 13)
52
VSAT
DC
ICL
IL
Saturation Voltage
Max Duty Cycle (ON)
Current Limit
Output Leakage
IOUT = 1A (Note 5)
Current
ISTBY
Quiescent Current
Standby Quiescent
Output = 0V
Output = −1V
(Note 7)
58/62
58/63
kHz(Max)
1.2/1.4
1.2/1.4
V(Max)
93
93
%(Min)
V
%
A
1.7/1.3
1.7/1.3
A(Min)
3.0/3.2
3.0/3.2
A(Max)
2
2
mA(Max)
30
30
mA(Max)
10/12
10
mA(Max)
200/500
200
µA(Max)
7.5
mA
5
ON /OFF Pin = 5V (OFF)
mA
50
Current
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kHz(Min)
2.2
Output = −1V
IQ
47/42
98
Peak Current (Notes 5, 13)
(Notes 7, 8)
47/43
0.9
(Note 6)
5
nA
kHz
µA
2018 NOV
LM1575/LM2575/LM2575HV
All Output Voltage Versions
Electrical Characteristics (Continued)
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 = 200 mA.
Symbol
Parameter
Conditions
Typ
LM1575-XX
LM2575-XX
Units
LM2575HV-XX (Limits)
Limit
Limit
(Note 2)
(Note 3)
DEVICE PARAMETERS
θJA
T Package, Junction to Ambient (Note 9)
65
θJA
Thermal Resistance
T Package, Junction to Ambient (Note 10)
45
θJC
T Package, Junction to Case
2
θJA
N Package, Junction to Ambient (Note 11)
85
θJA
M Package, Junction to Ambient (Note 11)
100
θJA
S Package, Junction to Ambient (Note 12)
37
˚C/W
ON /OFF CONTROL Test Circuit Figure 2
VIH
ON /OFF Pin Logic
VOUT = 0V
1.4
2.2/2.4
2.2/2.4
V(Min)
VIL
Input Level
VOUT = Nominal Output Voltage
1.2
1.0/0.8
1.0/0.8
V(Max)
ON /OFF Pin Input
ON /OFF Pin = 5V (OFF)
12
30
30
µA(Max)
10
10
µA(Max)
IIH
Current
IIL
ON /OFF Pin = 0V (ON)
µA
0
µA
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.
Note 2: All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). All limits are used to calculate Average
Outgoing Quality Level, and all are 100% production tested.
Note 3: All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). All room temperature limits are 100%
production tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.
Note 4: External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the
LM1575/LM2575 is used as shown in the Figure 2 test circuit, system performance will be as shown in system parameters section of Electrical Characteristics.
Note 5: Output (pin 2) sourcing current. No diode, inductor or capacitor connected to output pin.
Note 6: Feedback (pin 4) removed from output and connected to 0V.
Note 7: Feedback (pin 4) removed from output and connected to +12V for the Adjustable, 3.3V, and 5V versions, and +25V for the 12V and 15V versions, to force
the output transistor OFF.
Note 8: VIN = 40V (60V for the high voltage version).
Note 9: Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically, with 1⁄2 inch leads in a socket, or on a PC
board with minimum copper area.
Note 10: Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically, with 1⁄2 inch leads soldered to a PC board
containing approximately 4 square inches of copper area surrounding the leads.
Note 11: Junction to ambient thermal resistance with approximately 1 square inch of pc board copper surrounding the leads. Additional copper area will lower
thermal resistance further. See thermal model in Switchers made Simple software.
Note 12: If the TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper area thermally connected to the package: Using
0.5 square inches of copper area, θJA is 50˚C/W; with 1 square inch of copper area, θJA is 37˚C/W; and with 1.6 or more square inches of copper area, θJA is 32˚C/W.
Note 13: The oscillator frequency reduces to approximately 18 kHz in the event of an output short or an overload which causes the regulated output voltage to drop
approximately 40% from the nominal output voltage. This self protection feature lowers the average power dissipation of the IC by lowering the minimum duty cycle
from 5% down to approximately 2%.
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2018 NOV
LM1575/LM2575/LM2575HV
Typical Performance Characteristics
(Circuit of Figure 2)
Normalized Output Voltage
Line Regulation
Dropout Voltage
Current Limit
Quiescent Current
Standby
Quiescent Current
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2018 NOV
LM1575/LM2575/LM2575HV
Typical Performance Characteristics (Circuit of Figure 2)
(Continued)
Oscillator Frequency
Switch Saturation
Voltage
Efficiency
Minimum Operating Voltage
Quiescent Current
vs Duty Cycle
Feedback Voltage
vs Duty Cycle
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2018 NOV
LM1575/LM2575/LM2575HV
Typical Performance Characteristics (Circuit of Figure 2)
(Continued)
Feedback Pin Current
Maximum Power Dissipation
(TO-263) (See (Note 12))
Switching Waveforms
Load Transient Response
VOUT = 5V
A: Output Pin Voltage, 10V/div
B: Output Pin Current, 1A/div
C: Inductor Current, 0.5A/div
D: Output Ripple Voltage, 20 mV/div,
AC-Coupled
Horizontal Time Base: 5 µs/div
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.
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.
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2018 NOV
LM1575/LM2575/LM2575HV
Test Circuit and Layout Guidelines
(Continued)
Fixed Output Voltage Versions
CIN — 100 µF, 75V, Aluminum Electrolytic
COUT — 330 µF, 25V, Aluminum Electrolytic
D1 — Schottky, 11DQ06
L1 — 330 µH, PE-52627 (for 5V in, 3.3V out, use 100 µH, PE-92108)
Adjustable Output Voltage Version
where VREF = 1.23V, R1 between 1k and 5k.
R1 — 2k, 0.1%
R2 — 6.12k, 0.1%
FIGURE 2.
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2018 NOV