POWER MANAGEMENT
Description
The LM2575/6 series switching regulators are monolithic
integrated circuits designed for use in buck or buck/
boost regulator applications requiring accurate output
voltages over combined variations of line, load and
temperature. This unique series greatly simplifies
switching power supply design. The LM2575 has a
maximum output current of 1A and the LM2576 is rated
for 3A.
1A & 3A Miniconverter
Switching Regulators
Features
u
Pin for pin replacement for Nationals LM2575/6
u
series
DC-to-DC buck or buck/boost converter requiring
only 4 support components
Fixed or adjustable voltages
Preset output voltages of 3.3V, 5V and 12V
Wide output voltage range, 1.23V to 35V
82% typical efficiency @ 5V out
Wide input voltage range, 4V to 40V
Inhibit/enable control pin
Industrial temperature range
TO-220 and TO-263 packages
LM2575 & LM2576
u
u
u
u
The LM2575/6 series miniconverters include a
u
switching regulator and compensation network all within
u
the same package. Just add a choke, catch diode and
u
two capacitors to obtain an efficient DC-to-DC converter.
u
The current limit and thermal shutdown features of the
LM2575/6 series fully protect the device against
overstress conditions.
Applications
u
u
u
u
Micro controller power supplies
Medical equipment
Industrial power supplies
Instrumentation power supplies
The LM2575/6 series offers an alternative to popular 3
terminal linear regulators by providing higher efficiency
with reduced heatsink size. In many applications a heat
sink will not be required.
Typical Application Circuits
LM2575
L
1
D
1
C
IN
C
OUT
330µH
3A
68µF
330µF
LM2576
100µH
7A
120µF
1,000µF
Revision 1, January 2001
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LM2575 & LM2576
POWER MANAGEMENT
Absolute Maximum Ratings
Parameter
Input Voltage
On/Off Pi n Input Voltage
Output Voltage to C ommon (Steady State)
Power D i ssi pati on
Thermal Resi stance Juncti on to Ambi ent
TO-220
TO-263
Thermal Resi stance Juncti on to C ase
TO-220
TO-263
Operati ng Juncti on Temperature Range
Storage Temperature Range
Lead Temperature (Solderi ng) 10 Sec.
ESD Rati ng (Human Body Model)
P
D
q
JA
Sy mbol
V
IN
V
ON/OFF
Maximum
45
-0.3
£
V
ON/OFF
£
V
IN
-1
Internally Li mi ted
55
60
2.0
2.0
-40 to +125
-65 to +150
300
2
U nits
V
V
V
W
°C /W
q
JC
T
J
T
STG
T
LEAD
V
ESD
°C /W
°C
°C
°C
kV
Electrical Characteristics
Unless otherwise specified: V
IN
= 12V for 3.3V, 5V and ADJ options and 25V for 12V option; V
OUT
= 5V for ADJ option; T
A
= 25ºC; V
IN
rated = 40V;
I
O
= 0.5 to 3A (LM2576), 0.2 to 1A (LM2575). Values in
bold
apply over full operating temperature range.
Parameter
Output Voltage
LM2576-3.3
Sy mbol
V
O
Test C onditions
I
O
= 0.5A
8V to V
IN
Rated
Min
3.23
3.20
3.14
Ty p
3.30
Max
3.37
3.40
3.47
U nits
V
Output Voltage
LM2576-5
V
O
I
O
= 0.5A
8V to V
IN
Rated
4.90
4.85
4.75
5.00
5.10
5.15
5.25
V
Output Voltage
LM2576-12
V
O
I
O
= 0.5A
15V to V
IN
Rated
11.76
11.52
11.40
12.00
12.24
12.48
12.60
V
Feedback Voltage
LM2576-AD J, V
O
= 5V
V
FB
I
O
= 0.5A
8V to V
IN
Rated
1.217
1.193
1.180
1.230
1.243
1.267
1.280
V
Feedback Bi as C urrent
LM2576-AD J
ã
2001 Semtech Corp.
I
B
V
IN
= 12V, I
O
= 0.5A
50
100
500
nA
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LM2575 & LM2576
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Unless otherwise specified: V
IN
= 12V for 3.3V, 5V and ADJ options and 25V for 12V option; V
OUT
= 5V for ADJ option; T
A
= 25ºC; V
IN
rated = 40V;
I
O
= 0.5 to 3A (LM2576), 0.2 to 1A (LM2575). Values in
bold
apply over full operating temperature range.
Parameter
Output Voltage
LM2575-3.3
Sy mbol
V
O
Test C onditions
I
O
= 0.2A
8V to V
IN
Rated
Min
3.23
3.20
3.14
Ty p
3.30
Max
3.37
3.40
3.47
U nits
V
Output Voltage
LM2575-5
V
O
I
O
= 0.2A
8V to V
IN
Rated
4.90
4.85
4.75
5.00
5.10
5.15
5.25
V
Output Voltage
LM2575-12
V
O
I
O
= 0.2A
15V to V
IN
Rated
11.76
11.52
11.40
12.00
12.24
12.48
12.60
V
Feedback Voltage
LM2575-AD J, V
O
= 5V
V
FB
I
O
= 0.2A
8V to V
IN
Rated
1.217
1.193
1.180
1.230
1.243
1.267
1.280
V
Feedback Bi as C urrent
LM2575-AD J
Effi ci ency/Opti on
3.3V
5V
12V
A D J, V
O
= 5 V
Swi tchi ng Frequency
I
B
V
IN
= 12V, I
O
= 0.2A
50
100
500
nA
h
V
IN
= 12V, I
O
= 1A (LM2575, 3A for LM2576)
77
82
%
V
IN
= 15V, I
O
= 1A (LM2575, 3A for LM2576)
V
IN
= 12V, I
O
= 1A (LM2575, 3A for LM2576)
f
SX
47
43
88
82
52
58
62
0.9
0.9
93
1.7
1.3
98
2.2
3.0
3.2
5.8
6.9
7.5
A
1.2
1.4
%
A
V
kHz
Saturati on Voltage
(1)
V
SAT
LM2575, I
O
= 1A
LM2576, I
O
= 3A
Max. D uty C ycle (On)
(3)
Peak C urrent LM2575
(1)
DC
I
CL
Peak C urrent LM2576
(1)
I
CL
4.2
3.5
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LM2575 & LM2576
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Unless otherwise specified: V
IN
= 12V for 3.3V, 5V and ADJ options and 25V for 12V option; V
OUT
= 5V for ADJ option; T
A
= 25ºC; V
IN
rated = 40V;
I
O
= 0.5 to 3A (LM2576), 0.2 to 1A (LM2575). Values in
bold
apply over full operating temperature range.
Parameter
Output Leakage C urrent
(2)
Output = 0V
Output = -1V
Qui escent C urrent
(2)
Sy mbol
Test C onditions
Min
Ty p
Max
U nits
I
L
V
IN
= V
IN
Rated
7.5
2
30
10
12
mA
I
Q
5
mA
Standby Qui escent C urrent
(On/Off Pi n = 5V)
On/Off Pi n Logi c Input Level
I
STBY
50
500
µA
V
IH
2.2
2.4
1.4
V
V
IL
1.2
1.0
0.8
V
On/Off Pi n Input C urrent
I
IH
I
IL
V
ON/OFF
= 5V (Off)
V
ON/OFF
= 0V (On)
12
0
30
10
µA
Notes:
(1) Output sourcing current, resistive load, no inductor or capacitor.
(2) Feedback = V
O
+ 1.0V.
(3) Feedback = 0V.
ã
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LM2575 & LM2576
POWER MANAGEMENT
Pin Configurations
Ordering Information
D ev ice
(1)
LM2575T-XX
LM2575S-XX.TR
LM2576T-XX
LM2576S-XX.TR
P ackag e
TO-220-5
(2)(3)
TO-263-5
(4)
TO-220-5
(2)(3)
TO-263-5
(4)
3A
C urrent
1A
TO-263-5
LM2575, LM2576
Pin
Function
V
IN
OUTPUT
C OMMON
FE E D B A C K
ON/OFF
TO-220-5
1
2
3
4
5
Notes:
(1) -XX = Voltage Option. Available voltages are 3.3V
(-3.3), 5V (-5.0), 12V (-12), and ADJ (-ADJ), which is
adjustable between 1.23V and 35V.
(2) Lead bend options for TO-220-5 are: T-XX = Straight
in-line; T-XX-V = Vertical Staggered; T-XX-H = Horizontal
Staggered. Please refer to outline drawings at the end of
this datasheet.
(3) Only available in tube packaging. A tube contains 50
devices.
(4) Only available in tape and reel packaging. A reel
contains 800 devices.
TAB i s C OMMON
Block Diagram
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