1.0 & 3.0 AMP MINICONVERTER
SWITCHING REGULATORS
April 7, 1998
LM2575
LM2576
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
The LM2575/6 series switching regulators are mono-
lithic 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.
The LM2575/6 series miniconverters include a
switching regulator and compensation network all
within the same package. Just add a choke, catch
diode and two capacitors to obtain an efficient DC-to-
DC converter. Current limit and thermal shutdown
features of the LM2575/6 series fully protect the device
against overstress conditions.
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.
FEATURES
•
Pin for pin interchangeable with National’s
•
•
•
•
•
•
•
LM2575/LM2576 series
DC-to-DC buck or buck/boost converter requiring
only 4 support components
Fixed or adjustable voltages
Preset output voltages of 3.3, 5 and 12V
Wide output voltage range, 1.23 to 35V
82% typical efficiency @ 5V
Wide input voltage range, 4V to 40V
Inhibit/enable control pin
ABSOLUTE MAXIMUM RATINGS
Parameter
Input Voltage
On/Off Pin Input
Voltage
Output Voltage to
Common (Steady
State)
Power Dissipation
Thermal Resistance
Junction to Case
TO-220
TO-263
Thermal Resistance
Junction to Ambient
TO-220
TO-263
P
D
Symbol Maximum
V
IN
45
-0.3≤V≤V
IN
-1
Internally
Limited
Units
V
V
V
BLOCK DIAGRAM
W
θ
JC
2.0
2.0
°C/W
ORDERING INFORMATION
DEVICE
(1)
θ
JA
T
J
T
STG
T
LEAD
55
60
-40 to 125
-40 to 125
260
2
°C/W
°C
°C
°C
PACKAGE
TO-220
(2)
(3)
(2)
(3)
CURRENT
1A
LM2575T-XX
LM2575S-XX
LM2576T-XX
LM2576S-XX
Operating Junction
Temperature Range
Storage Temperature
Range
TO-263
TO-220
3A
TO-263
Lead Temperature
(Soldering) 10 Sec
ESD Class
Notes:
(1) XX = Voltage Option 3.3, 5.0, 12, and ADJ (1.23V
to 35V).
(2) T-XX = Straight in-line; T-XX-V = Vertical Stag-
gered; T-XX-H = Horizontal Staggered.
(3) Add suffix ‘TR’ for tape and reel (TO-263).
1
© 1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
1.0 & 3.0 AMP MINICONVERTER
SWITCHING REGULATORS
April 7, 1998
LM2575
LM2576
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, V
IN
= 12V for 3.3V, 5V and ADJ options; 25V for 12V; V
OUT
= 5V for ADJ, T
J
= 25ºC.
V
IN
rated = 40V; I
O
= 0.5 to 3A (LM2576), 0.2 to 1A (LM2575).
Test Conditions
Parameter
Output Voltage
LM2576-3.3
Symbol
V
O
8V to
V
IN
Rated
LM2576-5
V
O
8V to
V
IN
Rated
LM2576-12
V
O
15V to
V
IN
Rated
Feedback Voltage
V
OUT
= 5V
LM2576-ADJ
Feedback Bias Current
LM2576-ADJ
Output Voltage
LM2575-3.3
V
O
8V to
V
IN
Rated
LM2575-5
V
O
8V to
V
IN
Rated
LM2575-12
V
O
15V to
V
IN
Rated
Feedback Voltage
V
OUT
= 5V
LM2575-ADJ
Feedback Bias Current
LM2575-ADJ
I
B
I
FB
8V to
V
IN
Rated
12V
0.2A
O.T.
0.2A
O.T.
0.2A
O.T.
0.2A
O.T.
0.2A
O.T.
I
B
I
FB
8V to
V
IN
Rated
12V
0.5A
O.T.
3.23
3.14
3.20
4.90
4.75
4.85
11.76
11.40
11.52
1.217
1.180
1.193
3.30
3.30
3.30
5.00
5.00
5.00
12.00
12.00
12.00
1.230
1.230
1.230
0.5A
O.T.
0.5A
O.T.
0.5A
O.T.
V
IN
I
O
0.5A
O.T.
T
J
(4)
Test Limits
Min
3.23
3.14
3.20
4.90
4.76
4.85
11.76
11.40
11.52
1.217
1.180
1.193
Typ
3.30
3.30
3.30
5.00
5.00
5.00
12.00
12.00
12.00
1.230
1.230
1.230
50
Max
3.37
3.47
3.40
5.10
5.25
5.15
12.24
12.60
12.48
1.243
1.280
1.267
100
500
3.37
3.47
3.40
5.10
5.25
5.15
12.24
12.60
12.48
1.243
1.280
1.267
500
nA
V
V
V
V
nA
V
V
V
Units
V
(CONTINUED NEXT PAGE)
2
© 1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
1.0 & 3.0 AMP MINICONVERTER
SWITCHING REGULATORS
April 7, 1998
LM2575
LM2576
ELECTRICAL CHARACTERISTICS (cont.)
Test Conditions
Parameter
Efficiency/Option
3.3
5
12
ADJ V
O
= 5V
Switching Frequency
(1)
Test Limits
T
J
(4)
Symbol
η
V
IN
12V
I
O
LM2575-1A
LM2576-3A
Min
Typ
Max
Units
77
82
88
82
47
O.T.
43
52
52
0.9
0.9
93
4.2
O.T.
3.5
1.7
O.T.
1.3
2.2
98
5.8
6.9
7.5
3.0
3.2
58
62
1.2
1.4
%
15V
12V
F
SX
V
SAT
(3)
kHz
Saturation Voltage
LM2575-1A
LM2576-3A
O.T.
O.T.
V
Max Duty Cycle (On)
Current Limit
(1)
DC
I
CL
I
CL
(2)
%
A
Peak Current LM2576
Peak Current LM2575
A
Output Leakage Current
Output = 0V
Output = -1V
Quiescent Current
(2)
I
L
I
Q
V
IN
RATED
7.5
5
O.T.
2
30
10
12
50
O.T.
50
500
mA
mA
µA
Standby Quiescent
Current (On/Off Pin = 5V)
On/Off Pin Logic
Input Level
V
OUT
= 0V
V
OUT
= Option
On/Off Input Current
On/Off = 5V (Off)
On/Off = 0V (On)
I
STBY
V
IH
O.T.
V
IL
O.T.
2.2
2.4
1.4
1.4
1.2
1.2
1.0
0.8
V
V
I
IH
I
IL
0.5A
0.5A
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.
(4) Over Temp. (O.T.) = over specified operating junction temperature range.
3
© 1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
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