NSC LM2575T-ADJ, LM2575T-5.0, LM2575T-3.3, LM2575T-12, LM2575SX-ADJ Datasheet
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LM1575/LM2575/LM2575HV Series
SIMPLE SWITCHER
®
1A Step-Down Voltage Regulator
General Description
The LM2575 series of regulators are monolithic integrated
circuits that provide all the active functions for a step-down
(buck) switching regulator, capable of driving a 1A load with
excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5V, 12V, 15V, and an
adjustable output version.
Requiring aminimumnumber of external components, these
regulators are simple to use and include internal frequency
compensation and a fixed-frequency oscillator.
The LM2575 series offers a high-efficiency replacement for
popular three-terminal linear regulators. It substantially reduces the size of the heat sink, and in many cases no heat
sink is required.
A standard series of inductors optimized for use with the
LM2575 are available from several different manufacturers.
This feature greatly simplifies the design of switch-mode
power supplies.
Other features include a guaranteed
±
4%tolerance on output voltage within specified input voltages and output load
conditions, and
±
10%on the oscillator frequency. External
shutdown is included, featuring 50 µA (typical) standby current. The output switch includes cycle-by-cycle current limiting, as well as thermal shutdown for full protection under
fault conditions.
Features
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
Applications
n Simple high-efficiency step-down (buck) regulator
n Efficient pre-regualtor for linear regulators
n On-card switching regulators
n Positive to negative converter (Buck-Boost)
Typical Application (Fixed Output Voltage Versions)
SIMPLE SWITCHER®is a registered trademark of National Semiconductor Corporation.
DS011475-1
Note: Pin numbers are for the TO-220 package.
May 1999
LM1575/LM2575/LM2575HV Series SIMPLE SWITCHER 1A Step-Down Voltage Regulator
© 1999 National Semiconductor Corporation DS011475 www.national.com
Block Diagram and Typical Application
Connection Diagrams
(XX indicates output voltage option. See Ordering Information table for complete part
number.)
DS011475-2
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.
Straight Leads
5–Lead TO-22 (T)
DS011475-22
Top View
LM2575T-XX or LM2575HVT-XX
See NS Package Number T05A
Bent, Staggered Leads
5-Lead TO-220 (T)
DS011475-23
Top View
DS011475-24
Side View
LM2575T-XX Flow LB03 or
LM2575HVT-XX Flow LB03
See NS Package Number T05D
16–Lead DIP (N or J)
DS011475-25
*No Internal Connection
Top View
LM2575N-XX or LM2575HVN-XX
See NS Package Number N16A
LM1575J-XX-QML
See NS Package Number J16A
24-Lead Surface Mount (M)
DS011475-26
*No Internal Connection
Top View
LM2575M-XX or LM2575HVM-XX
See NS Package Number M24B
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Connection Diagrams (XX indicates output voltage option. See Ordering Information table for complete part
number.) (Continued)
Ordering Information
Package NSC Standard High Temperature
Type Package Voltage Rating Voltage Rating Range
Number (40V) (60V)
5-Lead TO-220 T05A LM2575T-3.3 LM2575HVT-3.3
Straight Leads LM2575T-5.0 LM2575HVT-5.0
LM2575T-12 LM2575HVT-12
LM2575T-15 LM2575HVT-15
LM2575T-ADJ LM2575HVT-ADJ
5-Lead TO-220 T05D LM2575T-3.3 Flow LB03 LM2575HVT-3.3 Flow LB03
Bent and LM2575T-5.0 Flow LB03 LM2575HVT-5.0 Flow LB03
Staggered Leads LM2575T-12 Flow LB03 LM2575HVT-12 Flow LB03
LM2575T-15 Flow LB03 LM2575HVT-15 Flow LB03
LM2575T-ADJ Flow LB03 LM2575HVT-ADJ Flow LB03
16-Pin Molded N16A LM2575N-5.0 LM2575HVN-5.0 −40˚C ≤ T
J
≤ +125˚C
DIP LM2575N-12 LM2575HVN-12
LM2575N-15 LM2575HVN-15
LM2575N-ADJ LM2575HVN-ADJ
24-Pin M24B LM2575M-5.0 LM2575HVM-5.0
Surface Mount LM2575M-12 LM2575HVM-12
LM2575M-15 LM2575HVM-15
LM2575M-ADJ LM2575HVM-ADJ
5-Lead TO-236 TS5B LM2575S-3.3 LM2575HVS-3.3
Surface Mount LM2575S-5.0 LM2575HVS-5.0
LM2575S-12 LM2575HVS-12
LM2575S-15 LM2575HVS-15
LM2575S-ADJ LM2575HVS-ADJ
16-Pin Ceramic J16A LM1575J-3.3-QML
DIP LM1575J-5.0-QML
LM1575J-12-QML −55˚C ≤ T
J
≤ +150˚C
LM1575J-15-QML
LM1575J-ADJ-QML
TO-263(S)
5-Lead Surface-Mount Package
DS011475-29
Top View
DS011475-30
Side View
LM2575S-XX or LM2575HVS-XX
See NS Package Number TS5B
www.national.com3
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Maximum Supply Voltage
LM1575/LM2575 45V
LM2575HV 63V
ON /OFF Pin Input Voltage
−0.3V ≤ V ≤ +V
IN
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)2kV
Lead Temperature
(Soldering, 10 sec.) 260˚C
Operating Ratings
Temperature Range
LM1575 −55˚C ≤ T
J
≤ +150˚C
LM2575/LM2575HV −40˚C ≤ T
J
≤ +125˚C
Supply Voltage
LM1575/LM2575 40V
LM2575HV 60V
LM1575-3.3, LM2575-3.3, LM2575HV-3.3
Electrical Characteristics
Specifications with standard type face are for T
J
=
25˚C, and those with boldface type apply over full Operating Tempera-
ture Range .
Symbol Parameter Conditions Typ LM1575-3.3 LM2575-3.3 Units
(Limits)
LM2575HV-3.3
Limit Limit
(Note 2) (Note 3)
SYSTEM PARAMETERS (Note 4) Test Circuit
Figure 2
V
OUT
Output Voltage V
IN
=
12V, I
LOAD
=
0.2A 3.3 V
Circuit of
Figure 2
3.267 3.234 V(Min)
3.333 3.366 V(Max)
V
OUT
Output Voltage 4.75V ≤ VIN≤ 40V, 0.2A ≤ I
LOAD
≤ 1A 3.3 V
LM1575/LM2575 Circuit of
Figure 2
3.200/3.168 3.168/3.135 V(Min)
3.400/3.432 3.432/3.465 V(Max)
V
OUT
Output Voltage 4.75V ≤ VIN≤ 60V, 0.2A ≤ I
LOAD
≤ 1A 3.3 V
LM2575HV Circuit of
Figure 2
3.200/3.168 3.168/3.135 V(Min)
3.416/3.450 3.450/3.482 V(Max)
η Efficiency V
IN
=
12V, I
LOAD
=
1A 75
%
LM1575-5.0, LM2575-5.0, LM2575HV-5.0
Electrical Characteristics
Specifications with standard type face are for T
J
=
25˚C, and those with boldface type apply over full Operating Tempera-
ture Range.
Symbol Parameter Conditions Typ LM1575-5.0 LM2575-5.0 Units
(Limits)
LM2575HV-5.0
Limit Limit
(Note 2) (Note 3)
SYSTEM PARAMETERS (Note 4) Test Circuit
Figure 2
V
OUT
Output Voltage V
IN
=
12V, I
LOAD
=
0.2A 5.0 V
Circuit of
Figure 2
4.950 4.900 V(Min)
5.050 5.100 V(Max)
V
OUT
Output Voltage 0.2A ≤ I
LOAD
≤ 1A, 5.0 V
LM1575/LM2575 8V ≤ V
IN
≤ 40V 4.850/4.800 4.800/4.750 V(Min)
Circuit of
Figure 2
5.150/5.200 5.200/5.250 V(Max)
V
OUT
Output Voltage 0.2A ≤ I
LOAD
≤ 1A, 5.0 V
LM2575HV 8V ≤ V
IN
≤ 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)
η Efficiency V
IN
=
12V, I
LOAD
=
1A 77
%
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LM1575-12, LM2575-12, LM2575HV-12
Electrical Characteristics
Specifications with standard type face are for T
J
=
25˚C, and those with boldface type apply over full Operating Tempera-
ture Range .
Symbol Parameter Conditions Typ LM1575-12 LM2575-12 Units
(Limits)
LM2575HV-12
Limit Limit
(Note 2) (Note 3)
SYSTEM PARAMETERS (Note 4) Test Circuit
Figure 2
V
OUT
Output Voltage V
IN
=
25V, I
LOAD
=
0.2A 12 V
Circuit of
Figure 2
11.88 11.76 V(Min)
12.12 12.24 V(Max)
V
OUT
Output Voltage 0.2A ≤ I
LOAD
≤ 1A, 12 V
LM1575/LM2575 15V ≤ V
IN
≤ 40V 11.64/11.52 11.52/11.40 V(Min)
Circuit of
Figure 2
12.36/12.48 12.48/12.60 V(Max)
V
OUT
Output Voltage 0.2A ≤ I
LOAD
≤ 1A, 12 V
LM2575HV 15V ≤ V
IN
≤ 60V 11.64/11.52 11.52/11.40 V(Min)
Circuit of
Figure 2
12.42/12.54 12.54/12.66 V(Max)
η Efficiency V
IN
=
15V, I
LOAD
=
1A 88
%
LM1575-15, LM2575-15, LM2575HV-15
Electrical Characteristics
Specifications with standard type face are for T
J
=
25˚C, and those with boldface type apply over full Operating Tempera-
ture Range .
Symbol Parameter Conditions Typ LM1575-15 LM2575-15 Units
(Limits)
LM2575HV-15
Limit Limit
(Note 2) (Note 3)
SYSTEM PARAMETERS (Note 4) Test Circuit
Figure 2
V
OUT
Output Voltage V
IN
=
30V, I
LOAD
=
0.2A 15 V
Circuit of
Figure 2
14.85 14.70 V(Min)
15.15 15.30 V(Max)
V
OUT
Output Voltage 0.2A ≤ I
LOAD
≤ 1A, 15 V
LM1575/LM2575 18V ≤ V
IN
≤ 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)
V
OUT
Output Voltage 0.2A ≤ I
LOAD
≤ 1A, 15 V
LM2575HV 18V ≤ V
IN
≤ 60V 14.55/14.40 14.40/14.25 V(Min)
Circuit of
Figure 2
15.525/15.675 15.68/15.83 V(Max)
η Efficiency V
IN
=
18V, I
LOAD
=
1A 88
%
LM1575-ADJ, LM2575-ADJ, LM2575HV-ADJ
Electrical Characteristics
Specifications with standard type face are for T
J
=
25˚C, and those with boldface type apply over full Operating Temperature
Range.
Symbol Parameter Conditions Typ LM1575-ADJ LM2575-ADJ Units
(Limits)
LM2575HV-ADJ
Limit Limit
(Note 2) (Note 3)
SYSTEM PARAMETERS (Note 4) Test Circuit
Figure 2
V
OUT
Feedback Voltage V
IN
=
12V, I
LOAD
=
0.2A 1.230 V
V
OUT
=
5V 1.217 1.217 V(Min)
Circuit of
Figure 2
1.243 1.243 V(Max)
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LM1575-ADJ, LM2575-ADJ, LM2575HV-ADJ
Electrical Characteristics
(Continued)
Specifications with standard type face are for T
J
=
25˚C, and those with boldface type apply over full Operating Temperature
Range.
Symbol Parameter Conditions Typ LM1575-ADJ LM2575-ADJ Units
(Limits)
LM2575HV-ADJ
Limit Limit
(Note 2) (Note 3)
SYSTEM PARAMETERS (Note 4) Test Circuit
Figure 2
V
OUT
Feedback Voltage 0.2A ≤ I
LOAD
≤ 1A, 1.230 V
LM1575/LM2575 8V ≤ V
IN
≤ 40V 1.205/1.193 1.193/1.180 V(Min)
V
OUT
=
5V, Circuit of
Figure 2
1.255/1.267 1.267/1.280 V(Max)
V
OUT
Feedback Voltage 0.2A ≤ I
LOAD
≤ 1A, 1.230 V
LM2575HV 8V ≤ V
IN
≤ 60V 1.205/1.193 1.193/1.180 V(Min)
V
OUT
=
5V, Circuit of
Figure 2
1.261/1.273 1.273/1.286 V(Max)
η Efficiency V
IN
=
12V, I
LOAD
=
1A, V
OUT
=
5V 77
%
All Output Voltage Versions
Electrical Characteristics
Specifications with standard type face are for T
J
=
25˚C, and those with boldface type apply over full Operating Temperature
Range. Unless otherwise specified, V
IN
=
12V for the 3.3V, 5V, and Adjustable version, V
IN
=
25V for the 12V version, and V
IN
=
30V for the 15V version. I
LOAD
=
200 mA.
Symbol Parameter Conditions Typ LM1575-XX LM2575-XX Units
(Limits)
LM2575HV-XX
Limit Limit
(Note 2) (Note 3)
DEVICE PARAMETERS
I
b
Feedback Bias
Current
V
OUT
=
5V (Adjustable Version Only) 50 100/500 100/500 nA
f
O
Oscillator Frequency (Note 13) 52 kHz
47/43 47/42 kHz(Min)
58/62 58/63 kHz(Max)
V
SAT
Saturation Voltage I
OUT
=
1A (Note 5) 0.9 V
1.2/1.4 1.2/1.4 V(Max)
DC Max Duty Cycle (ON) (Note 6) 98
%
93 93
%
(Min)
I
CL
Current Limit Peak Current (Notes 5, 13) 2.2 A
1.7/1.3 1.7/1.3 A(Min)
3.0/3.2 3.0/3.2 A(Max)
I
L
Output Leakage (Notes 7, 8) Output=0V 2 2 mA(Max)
Current Output=−1V 7.5 mA
Output=−1V 30 30 mA(Max)
I
Q
Quiescent Current (Note 7) 5 mA
10/12 10 mA(Max)
I
STBY
Standby Quiescent ON /OFF Pin=5V (OFF) 50 µA
Current 200/500 200 µA(Max)
θ
JA
Thermal Resistance T Package, Junction to Ambient (Note 9) 65
θ
JA
T Package, Junction to Ambient (Note 10) 45 ˚C/W
θ
JC
T Package, Junction to Case 2
θ
JA
N Package, Junction to Ambient (Note 11) 85
θ
JA
M Package, Junction to Ambient (Note 11) 100
θ
JA
S Package, Junction to Ambient (Note 12) 37
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All Output Voltage Versions
Electrical Characteristics
(Continued)
Specifications with standard type face are for T
J
=
25˚C, and those with boldface type apply over full Operating Temperature
Range. Unless otherwise specified, V
IN
=
12V for the 3.3V, 5V, and Adjustable version, V
IN
=
25V for the 12V version, and V
IN
=
30V for the 15V version. I
LOAD
=
200 mA.
Symbol Parameter Conditions Typ LM1575-XX LM2575-XX Units
(Limits)
LM2575HV-XX
Limit Limit
(Note 2) (Note 3)
ON /OFF CONTROL Test Circuit
Figure 2
V
IH
ON /OFF Pin Logic V
OUT
=
0V 1.4 2.2/2.4 2.2/2.4 V(Min)
V
IL
Input Level V
OUT
=
Nominal Output Voltage 1.2 1.0/0.8 1.0/0.8 V(Max)
I
IH
ON /OFF Pin Input ON /OFF Pin=5V (OFF) 12 µA
Current 30 30 µA(Max)
I
IL
ON /OFF Pin=0V (ON) 0µA
10 10 µA(Max)
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 limts 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%pro-
duction 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: V
IN
=
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
⁄2inch 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
⁄2inch 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 approxmiately 1 square inch of pc board copper surrounding the leads.Additionalcopperarea 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, θ
JA
is 50˚C/W; with 1 square inch of copper area, θJAis 37˚C/W; and with 1.6 or more square inches of copper area, θJAis 32˚C/W.
Note 13: The oscillator frequency reduces to approximately 18 kHz in the event of an output short or an overload which causes the regulated output voltage to drop
approximately 40%from the nominal output voltage. This self protection feature lowers the average power dissipation of the IC by lowering the minimum duty cycle
from 5%down to approximately 2%.
Note 14: Refer to RETS LM1575J for current revision of military RETS/SMD.
Typical Performance Characteristics (Circuit of
Figure 2
)
Normalized Output Voltage
DS011475-32
Line Regulation
DS011475-33
Dropout Voltage
DS011475-34
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Typical Performance Characteristics (Circuit of
Figure 2
) (Continued)
Current Limit
DS011475-35
Quiescent Current
DS011475-36
Standby
Quiescent Current
DS011475-37
Oscillator Frequency
DS011475-38
Switch Saturation
Voltage
DS011475-39
Efficiency
DS011475-40
Minimum Operating Voltage
DS011475-41
Quiescent Current
vs Duty Cycle
DS011475-42
Feedback Voltage
vs Duty Cycle
DS011475-43
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