LT1083/LT1084/LT1085
7.5A, 5A, 3A Low Dropout
Positive Adjustable Regulators
FeaTures
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DescripTion
The
LT
®
1083
series of positive adjustable regulators are
designed to provide 7.5A, 5A and 3A with higher efficiency
than currently available devices. All internal circuitry is
designed to operate down to 1V input-to-output differential
and the dropout voltage is fully specified as a function of
load current. Dropout is guaranteed at a maximum of 1.5V
at maximum output current, decreasing at lower load cur-
rents. On-chip trimming adjusts the reference voltage to
1%. Current limit is also trimmed, minimizing the stress
on both the regulator and power source circuitry under
overload conditions.
The LT1083/LT1084/LT1085 devices are pin compatible
with older 3-terminal regulators. A 10µF output capacitor
is required on these new devices. However, this is included
in most regulator designs.
Unlike PNP regulators, where up to 10% of the output cur-
rent is wasted as quiescent current, the LT1083 quiescent
current flows into the load, increasing efficiency.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
UltraFast and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
3-Terminal Adjustable
Output Current of 3A, 5A or 7.5A
Operates Down to 1V Dropout
Guaranteed Dropout Voltage at Multiple Current Levels
Line Regulation: 0.015%
Load Regulation: 0.1%
100% Thermal Limit Functional Test
Fixed Versions Available
Available in 3-Lead Plastic TO-220 and DD Packages
applicaTions
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High Efficiency Linear Regulators
Post Regulators for Switching Supplies
Constant Current Regulators
Battery Chargers
DEVICE
LT1083
LT1084
LT1085
OUTPUT CURRENT*
7.5A
5.0A
3.0A
*For a 1.5A low dropout regulator see the LT1086 data sheet.
Typical applicaTion
Dropout Voltage vs Output Current
INPUT/OUTPUT VOLTAGE DIFFERENTIAL (V)
5V, 7.5A Regulator
2
V
IN
≥ 6.5V
IN
LT1083
ADJ
OUT
121
1%
365
1%
5V AT 7.5A
+
10µF
+
10µF*
TANTALUM
1
*REQUIRED FOR STABILITY
1083/4/5 ADJ TA01
0
0
OUTPUT CURRENT
I
FULL LOAD
1083/4/5 ADJ TA02
108345fh
For more information
www.linear.com/LT1083
1
LT1083/LT1084/LT1085
absoluTe MaxiMuM raTings
(Note 1)
Power Dissipation ............................... Internally Limited
Input-to-Output Voltage Differential
C-Grades...............................................................30V
I-Grades ................................................................30V
M-Grades
(OBSOLETE)
........................................35V
Operating Junction Temperature Range (Note 9)
C-Grades: Control Section ................... 0°C to 125°C
Power Transistor ................. 0°C to 150°C
I-Grades: Control Section ...............– 40°C to 125°C
Power Transistor .............– 40°C to 150°C
M-Grades:
(OBSOLETE)
Control Section ...............– 55°C to 150°C
Power Transistor ............. –55°C to 200°C
Storage Temperature Range ..................– 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
preconDiTioning
100% thermal shutdown functional test.
pin conFiguraTion
FRONT VIEW
TAB
IS
OUTPUT
3
2
1
T PACKAGE
3-LEAD PLASTIC TO-220
θ
JA
= 50°C/W
V
IN
V
OUT
ADJ
TAB IS
OUTPUT
FRONT VIEW
3
2
1
P PACKAGE
3-LEAD PLASTIC TO-3P
θ
JA
= 35°C/W
V
IN
V
OUT
ADJ
OBSOLETE PACKAGE
CASE IS
OUTPUT
FRONT VIEW
TAB
IS
OUTPUT
3
2
1
M PACKAGE
3-LEAD PLASTIC DD
θ
JA
= 30°C/W*
*WITH PACKAGE SOLDERED TO 0.5IN
2
COPPER AREA OVER
BACKSIDE GROUND PLANE OR INTERNAL POWER PLANE.
θ
JA
CAN VARY
FROM 20°C/W TO >40°C/W DEPENDING ON MOUNTING TECHNIQUE
V
IN
V
OUT
ADJ
BOTTOM VIEW
V
IN
2
1
ADJ
K PACKAGE
2-LEAD TO-3 METAL CAN
θ
JA
= 35°C/W
OBSOLETE PACKAGE
2
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For more information
www.linear.com/LT1083
LT1083/LT1084/LT1085
orDer inForMaTion
LEAD BASED FINISH
LT1083CK
LT1083MK
LT1084CK
LT1084MK
LT1085CK
LT1085MK
TAPE AND REEL
NA
NA
NA
NA
NA
NA
PART MARKING
LT1083CK
LT1083MK
LT1084CK
LT1084MK
LT1085CK
LT1085MK
PACKAGE DESCRIPTION
2-Lead TO-3 Metal Can
2-Lead TO-3 Metal Can
2-Lead TO-3 Metal Can
2-Lead TO-3 Metal Can
2-Lead TO-3 Metal Can
2-Lead TO-3 Metal Can
TEMPERATURE RANGE
Control: 0°C to 125°C
Power: 0°C to 150°C
Control: –55°C to 150°C
Power: –55°C to 200°C
Control: 0°C to 125°C
Power: 0°C to 150°C
Control: –55°C to 150°C
Power: –55°C to 200°C
Control: 0°C to 125°C
Power: 0°C to 150°C
Control: –55°C to 150°C
Power: –55°C to 200°C
OBSOLETE PACKAGE
Consult LTC Marketing for parts specified with wider operating temperature ranges.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
4
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For more information
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LT1083/LT1084/LT1085
temperature range, otherwise specifications are at T
A
= 25°C.
PARAMETER
Reference Voltage
CONDITIONS
I
OUT
= 10mA, T
J
= 25°C,
(V
IN
– V
OUT
) = 3V
10mA ≤ I
OUT
≤ I
FULL_LOAD
1.5V ≤ (V
IN
– V
OUT
) ≤ 25V (Notes 4, 6, 7)
I
LOAD
= 10mA, 1.5V ≤ (V
IN
– V
OUT
) ≤ 15V, T
J
= 25°C (Notes 2, 3)
l
elecTrical characTerisTics
The
l
denotes the specifications which apply over the full operating
MIN
1.238
l
TYP
1.250
1.250
0.015
0.035
0.05
0.05
0.1
0.2
1.3
MAX
1.262
1.270
0.2
0.2
0.5
0.5
0.3
0.4
1.5
UNITS
V
V
%
%
%
%
%
%
V
A
A
A
A
A
A
1.225
Line Regulation
M-Grade: 15V ≤ (V
IN
– V
OUT
) ≤ 35V (Notes 2, 3)
C-, I-Grades: 15V ≤ (V
IN
– V
OUT
) ≤ 30V (Notes 2, 3)
Load Regulation
Dropout Voltage
Current Limit
LT1083
LT1084
LT1085
Minimum Load Current
Thermal Regulation
LT1083
LT1084
LT1085
Ripple Rejection
Adjust Pin Current
Adjust Pin Current Change
Temperature Stability
Long-Term Stability
RMS Output Noise (% of V
OUT
)
Thermal Resistance Junction-to-Case
LT1083
LT1084
LT1085
T
A
= 125°C, 1000 Hrs
T
A
= 25°C, 10Hz = ≤ f ≤ 10kHz
Control Circuitry/Power Transistor
K Package
P Package
K Package
P Package
T Package
K Package
M, T Package
(V
IN
– V
OUT
) = 3V, 10mA ≤ I
OUT
≤ I
FULL_LOAD
, T
J
= 25°C
(Notes 2, 3, 4, 6)
∆V
REF
= 1%, I
OUT
= I
FULL_LOAD
(Notes 5, 6, 8)
(V
IN
– V
OUT
) = 5V
(V
IN
– V
OUT
) = 25V
(V
IN
– V
OUT
) = 5V
(V
IN
– V
OUT
) = 25V
(V
IN
– V
OUT
) = 5V
(V
IN
– V
OUT
) = 25V
(V
IN
– V
OUT
) = 25V
T
A
= 25°C, 30ms Pulse
l
l
l
l
l
l
l
l
l
l
l
8.0
0.4
5.5
0.3
3.2
0.2
9.5
1.0
6.5
0.6
4.0
0.5
5
0.002
0.003
0.004
10
0.010
0.015
0.020
mA
%/W
%/W
%/W
dB
µA
µA
µA
%
%
%
f = 120Hz, C
ADJ
= 25µF, C
OUT
= 25µF Tantalum
I
OUT
= I
FULL_LOAD
, (V
IN
– V
OUT
) = 3V (Notes 6, 7, 8)
T
J
= 25°C
l
60
75
55
l
120
5
1
10mA ≤ I
OUT
≤ I
FULL_LOAD
, 1.5V ≤ (V
IN
– V
OUT
) ≤ 25V (Note 6)
l
l
0.2
0.5
0.3
0.003
0.6/1.6
0.5/1.6
0.75/2.3
0.65/2.3
0.65/2.7
0.9/3.0
0.7/3.0
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
108345fh
For more information
www.linear.com/LT1083
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