LT1083/LT1084/LT1085 Fixed
3A, 5A, 7.5A Low Dropout
Positive Fixed Regulators
Features
Description
Three-Terminal 3.3V, 3.6V, 5V and 12V
nn Output Current of 3A, 5A or 7.5A
nn Operates Down to 1V Dropout
nn Guaranteed Dropout Voltage at Multiple Current Levels
nn Line Regulation: 0.015%
nn Load Regulation: 0.1%
nn 100% Thermal Limit Functional Test
nn Adjustable Versions Available
Applications
The LT®1083 series of positive adjustable regulators are
designed to provide 3A, 5A and 7.5A 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
currents. On-chip trimming adjusts the output voltage to
1%. Current limit is also trimmed, minimizing the stress
on both the regulator and power source circuitry under
overload conditions.
High Efficiency Linear Regulators
Post Regulators for Switching Supplies
nn Constant Current Regulators
nn Battery Chargers
The LT1083 series devices are pin compatible with older
three-terminal regulators. A 10µF output capacitor is
required on these new devices; however, this is usually
included in most regulator designs.
nn
nn
nn
DEVICE
OUTPUT CURRENT*
LT1083
LT1084
LT1085
7.5 Amps
5.0 Amps
3.0 Amps
*For a 1.5A low dropout regulator see the LT1086 data sheet.
Unlike PNP regulators, where up to 10% of the output current is wasted as quiescent current, the LT1083 quiescent
current flows into the load, increasing efficiency.
L, LT, LTC, LTM, Linear Technology, the Linear logo and OPTI-LOOP are registered trademarks
and UltraFast is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
Typical Application
5V, 7.5A Regulator
5V AT 7.5A
LT1083-5
+
+
10µF
22µF*
TANTALUM
LT1083/4/5 TA01
*REQUIRED FOR STABILITY
INPUT/OUTPUT VOLTAGE DIFFERENTIAL (V)
VIN ≥ 6.5V
Dropout Voltage vs Output Current
2
1
0
0
IFULLLOAD/2
OUTPUT CURRENT (A)
IFULLLOAD
1083/4/5 TA02
1083ffe
For more information www.linear.com/LT1083
1
LT1083/LT1084/LT1085 Fixed
Absolute Maximum Ratings
(Note 1)
Power Dissipation............................... Internally Limited
Input Voltage*........................................................... 30V
Operating Input Voltage
3.3V, 3.6V Devices................................................ 20V
5V Devices............................................................ 20V
12V Devices.......................................................... 25V
Operating Junction Temperature Range
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
*Although the devices maximum operating voltage is limited, (20V for
a 3V, 5V device, and 25V for a 12V device) the devices are guaranteed
to withstand transient input voltages up to 30V. For input voltages
greater than the maximum operating input voltage some degradation of
specifications will occur. For input/output voltage differentials greater than
15V, a minimum external load of 5mA is required to maintain regulation.
preconditioning
100% Thermal Limit Functional Test.
Order Information
TAB IS
OUTPUT
FRONT VIEW
TAB IS
OUTPUT
3
VIN
2
VOUT
1
GND
VIN
2
VOUT
1
GND
θJA = 35°C/W
OBSOLETE PACKAGE
θJA = 50°C/W
FRONT VIEW
CASE IS
OUTPUT
2
TAB IS
OUTPUT
1
GND
K PACKAGE
2-LEAD TO-3 METAL CAN
θJA = 35°C/W
OBSOLETE PACKAGE
2
3
P PACKAGE
3-LEAD TO-3P PLASTIC
T PACKAGE
3-LEAD PLASTIC TO-220
VIN
FRONT VIEW
3
VIN
2
VOUT
1
GND
M PACKAGE
3-LEAD PLASTIC DD
θJA = 30°C/W*
*WITH PACKAGE SOLDERED TO 0.5IN2 COPPER AREA OVER
BACKSIDE GROUND PLANE OR INTERNAL POWER PLANE. θJA CAN VARY
FROM 20°C/W TO >40°C/W DEPENDING ON MOUNTING TECHNIQUE
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LT1083/LT1084/LT1085 Fixed
Order Information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT1083CP-5#PBF
NA
LT1083CP-5
3-Lead Plastic TO-3P
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1083CP-12#PBF
NA
LT1083CP-12
3-Lead Plastic TO-3P
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1084CP-5#PBF
NA
LT1084CP-5
3-Lead Plastic TO-3P
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1084CP-12#PBF
NA
LT1084CP-12
3-Lead Plastic TO-3P
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1084CT-3.3#PBF
NA
LT1084CT-3.3
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1084CT-5#PBF
NA
LT1084CT-5
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1084CT-12#PBF
NA
LT1084CT-12
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CT-3.3#PBF
NA
LT1085CT-3.3
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CT-3.6#PBF
NA
LT1085CT-3.6
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CT-5#PBF
NA
LT1085CT-5
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CT-12#PBF
NA
LT1085-12
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CM-3.3#PBF
LT1085CM-3.3#TRPBF
LT1085CM-3.3
3-Lead Plastic DD
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CM-3.6#PBF
LT1085CM-3.6#TRPBF
LT1085CM-3.6
3-Lead Plastic DD
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085IM-3.6#PBF
LT1085IM-3.6#TRPBF
LT1085IM-3.6
3-Lead Plastic DD
Control: –40°C to 125°C
Power: –40°C to 150°C
OBSOLETE PACKAGE
LEAD BASED FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT1083CP-5
NA
LT1083CP-5
3-Lead Plastic TO-3P
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1083CP-12
NA
LT1083CP-12
3-Lead Plastic TO-3P
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1084CP-5
NA
LT1084CP-5
3-Lead Plastic TO-3P
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1084CP-12
NA
LT1084CP-12
3-Lead Plastic TO-3P
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1083CK-5
NA
LT1083CK-5
2-Lead TO-3 Metal Can
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1083CK-12
NA
LT1083CK-12
2-Lead TO-3 Metal Can
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1083MK-5
NA
LT1083MK-5
2-Lead TO-3 Metal Can
Control: –55°C to 150°C
Power: –55°C to 200°C
LT1083MK-12
NA
LT1083MK-12
2-Lead TO-3 Metal Can
Control: –55°C to 150°C
Power: –55°C to 200°C
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3
LT1083/LT1084/LT1085 Fixed
Order Information
LEAD BASED FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT1084CK-5
NA
LT1084CK-5
2-Lead TO-3 Metal Can
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1084CK-12
NA
LT1084CK-12
2-Lead TO-3 Metal Can
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1084MK-5
NA
LT1084MK-5
2-Lead TO-3 Metal Can
Control: –55°C to 150°C
Power: –55°C to 200°C
LT1084MK-12
NA
LT1084MK-12
2-Lead TO-3 Metal Can
Control: –55°C to 150°C
Power: –55°C to 200°C
LT1085CK-5
NA
LT1085CK-5
2-Lead TO-3 Metal Can
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CK-12
NA
LT1085CK-12
2-Lead TO-3 Metal Can
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085MK-5
NA
LT1085MK-5
2-Lead TO-3 Metal Can
Control: –55°C to 150°C
Power: –55°C to 200°C
LT1085MK-12
NA
LT1085MK-12
2-Lead TO-3 Metal Can
Control: –55°C to 150°C
Power: –55°C to 200°C
OBSOLETE PACKAGE
LT1084CT-3.3
NA
LT1084CT-3.3
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1084CT-5
NA
LT1084CT-5
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1084CT-12
NA
LT1084CT-12
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CT-3.3
NA
LT1085CT-3.3
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CT-3.6
NA
LT1085CT-3.6
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CT-5
NA
LT1085CT-5
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CT-12
NA
LT1085-12
3-Lead Plastic TO-220
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CM-3.3
LT1085CM-3.3#TR
LT1085CM-3.3
3-Lead Plastic DD
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085CM-3.6
LT1085CM-3.6#TR
LT1085CM-3.6
3-Lead Plastic DD
Control: 0°C to 125°C
Power: 0°C to 150°C
LT1085IM-3.6
LT1085IM-3.6#TR
LT1085IM-3.6
3-Lead Plastic DD
Control: –40°C to 125°C
Power: –40°C to 150°C
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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LT1083/LT1084/LT1085 Fixed
Electrical
Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C.
PARAMETER
CONDITIONS
Output Voltage
LT1084-3.3
LT1085-3.3
LT1085-3.6
Line Regulation
UNITS
IOUT = 0mA, TJ = 25°C, VIN = 8V (K Package Only)
4.8V ≤ VIN ≤ 15V, 0 ≤ IOUT ≤ IFULL_LOAD (Notes 3, 4, 9)
l
3.270
3.235
3.300
3.300
3.330
3.365
V
V
VIN = 5V, IOUT = 0mA, TJ = 25°C (K Package Only)
4.8V ≤ VIN ≤ 15V, 0 ≤ IOUT ≤ IFULL_LOAD (Notes 3, 4, 9)
l
3.270
3.235
3.300
3.300
3.330
3.365
V
V
VIN = 5V, IOUT = 0mA, TJ = 25°C (K Package Only)
5V ≤ VIN ≤ 15V, 0 ≤ IOUT ≤ IFULL_LOAD (Note 9)
5V ≤ VIN ≤ 15V, 0 ≤ IOUT ≤ IFULL_LOAD, TJ ≥ 0°C (Notes 3, 4, 9)
3.564
3.500
3.528
3.600
l
3.636
3.672
3.672
V
V
V
3.672
3.672
3.672
3.672
V
V
V
V
LT1083/4/5-5
IOUT = 0mA, TJ = 25°C, VIN = 8V (K Package Only)
0 ≤ IOUT ≤ IFULL_LOAD, 6.5V ≤ VIN ≤ 20V (Notes 4, 6, 7, 9)
4.950
4.900
5.000
5.000
5.050
5.100
V
V
LT1083/4/5-12
IOUT = 0mA, TJ = 25°C, VIN = 15V (K Package Only)
0 ≤ IOUT ≤ IFULL_LOAD, 13.5V ≤ VIN ≤ 25V (Notes 4, 6, 7, 9)
11.880
11.760
12.000
12.000
12.120
12.240
V
V
LT1084-3.3
IOUT = 0mA, TJ = 25°C, 4.8V ≤ VIN ≤ 15V
l
0.5
1.0
6
6
mV
mV
l
0.5
1.0
6
6
mV
mV
l
0.5
1.0
6
6
mV
mV
l
0.5
1.0
10
10
mV
mV
l
1.0
2.0
25
25
mV
mV
l
3
7
15
20
mV
mV
l
3
7
15
20
mV
mV
l
3
7
15
20
mV
mV
l
5
10
20
35
mV
mV
l
12
24
36
72
mV
mV
LT1083/4/5-5
LT1083/4/5-12
LT1084-3.3
LT1085-3.3
LT1085-3.6
LT1083/4/5-5
LT1083/4/5-12
Current Limit
MAX
5V ≤ VIN ≤ 15V, 0 ≤ IOUT ≤ 2.5A (Notes 3, 4, 9)
VIN = 4.75V, IOUT = 3A, TJ ≥ 0°C
VIN = 4.75V, IOUT = 2.5A, TJ ≥ 0°C
VIN = 4.75V, IOUT = 1.5A, TJ > 0°C
LT1085-3.6
Dropout Voltage
TYP
LT1085-3.6
LT1085-3.3
Load Regulation
MIN
l
3.528
3.350
3.450
3.528
4.8V ≤ VIN ≤ 15V, IOUT = 0mA, TJ= 25°C
4.8V ≤ VIN ≤ 15V, IOUT = 0mA, TJ= 25°C
IOUT = 0mA, TJ = 25°C, 6.5V ≤ VIN ≤ 20V (Notes 2, 3)
IOUT = 0mA, TJ = 25°C, 13.5V ≤ VIN ≤ 25V (Notes 2, 3)
VIN = 5V, 0 ≤ IOUT ≤ 5A, TJ = 25°C
VIN = 5V, 0 ≤ IOUT ≤ 3A, TJ = 25°C
VIN = 5.25V, 0 ≤ IOUT ≤ 3A, TJ = 25°C
VIN = 8V, 0 ≤ IOUT ≤ IFULL_LOAD, TJ = 25°C (Notes 2, 3, 4, 6)
VIN = 15V, 0 ≤ IOUT ≤ IFULL_LOAD, TJ = 25°C (Notes 2, 3, 4, 6)
LT1084/5-3.3
∆VOUT = 33mV, IOUT = IFULL_LOAD (Notes 5, 6)
l
1.3
1.5
V
LT1085-3.6
∆VOUT = 36mV, IOUT = IFULL_LOAD (Notes 5, 6)
l
1.3
1.5
V
LT1083/4/5-5
∆VOUT = 50mV, IOUT = IFULL_LOAD (Notes 5, 6)
l
1.3
1.5
V
LT1083/4/5-12
∆VOUT = 120mV, IOUT = IFULL_LOAD (Notes 5, 6)
l
1.3
1.5
LT1083-5
VIN = 10V
l
8.0
9.5
A
LT1083-12
VIN = 17V
l
8.0
9.5
A
LT1084-3.3
VIN = 8V
l
5.5
6.5
A
LT1084-5
VIN = 10V
l
5.5
6.5
A
LT1084-12
VIN = 17V
l
5.5
6.5
A
LT1085-3.3/3.6
VIN = 8V
l
3.2
4.0
A
LT1085-5
VIN = 10V
l
3.2
4.0
A
LT1085-12
VIN = 17V
l
3.2
4.0
A
V
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5
LT1083/LT1084/LT1085 Fixed
Electrical
Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C.
PARAMETER
CONDITIONS
TYP
MAX
UNITS
Quiescent Current
LT1084-3.3
VIN = 18V
l
MIN
5.0
10.0
mA
LT1085-3.3
VIN = 18V
l
5.0
10.0
mA
LT1085-3.6
VIN = 18V
l
5.0
10.0
mA
LT1083/4/5-5
VIN ≤ 20V
l
5.0
10.0
mA
LT1083/4/5-12
VIN ≤ 25V
l
Thermal Regulation
LT1083-5/12
TA = 25°C, 30ms pulse
LT1084-3.3/5/12
LT1085-3.3/3.6/5/12
Ripple Rejection
f = 120Hz, COUT = 25µF Tantalum, IOUT = IFULL_LOAD (Note 4)
LT1084-3.3
f = 120Hz, COUT = 25µF Tantalum, IOUT = 5A, VIN = 6.3V
LT1085-3.3
f = 120Hz, COUT = 25µF Tantalum, VIN = 6.3V, IOUT = 3A
LT1085-3.6
f = 120Hz, COUT = 25µF Tantalum, VIN = 6.6V, IOUT = 3A
LT1083/4/5-5
VIN = 8V (Note 6)
LT1083/4/5-12
VIN = 15V (Note 6)
Temperature Stability
l
l
l
l
l
l
60
60
60
60
54
5.0
10.0
mA
0.002
0.003
0.004
0.010
0.015
0.020
%/W
%/W
%/W
0.5
Long Term Stability
TA = 125°C, 1000 Hrs.
0.03
RMS Output Noise
(% of VOUT)
TA = 25°C,
10Hz = ≤ f ≤ 10kHz
0.003
Thermal Resistance
Junction-to-Case
Control Circuitry/Power Transistor (See Applications Information)
LT1083
K Package
P Package
%
1.0
%
%
0.6/1.6
0.5/1.6
°C/W
°C/W
LT1084
K Package
P Package
T Package
0.75/2.3
0.65/2.3
0.65/2.7
°C/W
°C/W
°C/W
LT1085
K Package
T Package
DD Package
0.9/3.0
0.7/3.0
0.7/3.0
°C/W
°C/W
°C/W
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: See thermal regulation specifications for changes in output voltage
due to heating effects. Load and line regulation are measured at a constant
junction temperature by low duty cycle pulse testing.
Note 3: Line and load regulation are guaranteed up to the maximum power
dissipation (60W for the LT1083, 45W for the LT1084 (K, P), 30W for the
LT1084 (T) and 30W for the LT1085). Power dissipation is determined by
the input/output differential and the output current. Guaranteed maximum
power dissipation will not be available over the full input/output range.
Note 4: IFULL_LOAD is defined in the current limit curves. The IFULL_LOAD
curve is defined as the minimum value of current limit as a function of
input to output voltage. Note that the 60W power dissipation for the
LT1083 (45W for the LT1084 (K, P), 30W for the LT1084 (T), 30W for the
LT1085) is only achievable over a limited range of input to output voltage.
6
dB
dB
dB
dB
dB
72
72
72
68
60
Note 5: Dropout voltage is specified over the full output current range of
the device. Test points and limits are shown on the Dropout Voltage curve.
Note 6: For LT1083 IFULL_LOAD is 5A for – 55°C ≤ TJ ≤ – 40°C and 7.5A for
TJ ≥ – 40°C.
Note 7: 1.7V ≤ (VIN – VOUT) ≤ 25V for LT1084 at – 55°C ≤ TJ ≤ – 40°C.
Note 8: Dropout voltage 1.7V maximum for LT1084 at
– 55°C ≤ TJ ≤ –40°C.
Note 9: Full load current is not available at all input-output voltages.
See Notes 3, 4, 6.
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LT1083/LT1084/LT1085 Fixed
Typical Performance Characteristics
LT1083 Short-Circuit Current
–40°C ≤ TJ ≤ 150°C
0°C ≤ TJ ≤ 125°C
TJ = 150°C
TJ = 25°C
TJ = –55°C
1
2
3 4 5 6 7 8
OUTPUT CURRENT (A)
9
10
8
6
– 55°C
4
2
0
10
150°C
IFULL_LOAD
GUARANTEED
0
20
30
15
25
5
10
INPUT/OUTPUT DIFFERENTIAL (V)
SHORT-CIRCUIT CURRENT (A)
MINIMUN INPUT/OUTPUT DIFFERENTIAL (V)
0°C ≤ TJ ≤ 125°C
TJ = – 55°C
1
TJ = 25°C
7
150°C
25°C
6
–55°C
5
4
3
IFULL_LOAD
GUARANTEED
2
3
4
2
OUTPUT CURRENT (A)
5
0
6
0
20
15
10
25
30
5
INPUT/OUTPUT DIFFERENTIAL (V)
LT1083/4/5 FIXEDG04
SHORT-CIRCUIT CURRENT (A)
MINIMUM INPUT/OUTPUT DIFFERENTIAL (V)
INDICATES GUARANTEED TEST POINT
1
TJ = –55°C
TJ = 150°C
0
0
0.05
0
–0.05
–0.10
–0.15
TJ = 25°C
3
2
1
OUTPUT CURRENT (A)
4
LT1083/4/5 FIXED G07
0
25 50 75 100 125 150
TEMPERATURE (°C)
LT1083/4/5 FIXED G06
LT1085 Short-Circuit Current
0°C ≤ TJ ≤ 125°C
25 50 75 100 125 150
TEMPERATURE (°C)
∆I = 5A
–0.20
–50 –25
35
LT1085 Load Regulation
6
– 55°C ≤ TJ ≤ 150°C
0
LT1083/4/5 FIXED G05
LT1085 Dropout Voltage
2
–0.15
LT1084 Load Regulation
8
1
0
–0.10
0.10
9
– 55°C ≤ TJ ≤ 150°C
0
–0.05
LT1083/4/5 FIXED G03
10
INDICATES GUARANTEED TEST POINT
TJ = 150°C
0
LT1084 Short Circuit Current
LT1084 Dropout Voltage
1
0.05
LT1083/4/5 FIXED G02
LT1083/4/5 FIXED G01
2
∆I = 7.5A
–0.20
–50 –25
35
OUTPUT VOLTAGE DEVIATION (%)
0
25°C
0.10
OUTPUT VOLTAGE DEVIATION (%)
0
0.10
OUTPUT VOLTAGE DEVIATION (%)
INDICATES GUARANTEED TEST POINT
1
LT1083 Load Regulation
12
SHORT-CIRCUIT CURRENT (A)
MINIMUM INPUT/OUTPUT DIFFERENTIAL (V)
LT1083 Dropout Voltage
2
5
25°C
4
150°C
3
–55°C
2
IFULL_LOAD
GUARANTEED
1
0
0
20
30
15
25
5
10
INPUT/OUTPUT DIFFERENTIAL (V)
35
LT1083/4/5 FIXED G08
∆I = 3A
0.05
0
–0.05
–0.10
–0.15
–0.20
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
LT1083/4/5 FIXED G09
1083ffe
For more information www.linear.com/LT1083
7
LT1083/LT1084/LT1085 Fixed
Typical Performance Characteristics
LT1083/4/5-5 Ripple Rejection
vs Current
LT1083/4/5-5 Ripple Rejection
VRIPPLE ≤ 3VP-P
VRIPPLE
≤ 0.5VP-P
50
80
(VIN – VOUT) ≥ 3V
60
(VIN – VOUT) ≥ VDROPOUT
40
30
20
fR = 120Hz
VRIPPLE ≤ 3VP-P
70
fR = 20kHz
VRIPPLE ≤ 0.5VP-P
60
50
40
30
20
10
IOUT = IFULL_LOAD
0
10
100
1k
10k
FREQUENCY (Hz)
2.0
90
RIPPLE REJECTION (dB)
RIPPLE REJECTION (dB)
70
0
100k
0
0.8
0.2
0.6
0.4
OUTPUT CURRENT (0 TO IFULLLOAD)
(VIN – VOUT) ≥ VDROPOUT
20
100
90
1k
10k
FREQUENCY (Hz)
70
60
fR = 20kHz
VRIPPLE ≤ 0.5VP-P
50
40
IOUT = IFULL_LOAD
100
80
fR = 120Hz
VRIPPLE ≤ 3VP-P
70
10
0
10
25 50 75 100 125 150
TEMPERATURE (°C)
LT1083 Maximum Power
Dissipation*
50
40
30
20
20
10
10
0
0.8
0.2
0.6
0.4
OUTPUT CURRENT (0 TO IFULLLOAD)
1083/4/5 FIXED G13
1.0
1083/4/5 FIXED G14
LT1083MK
60
30
0
100k
POWER (W)
(VIN – VOUT) ≥ 3V
30
0
LT1183/4/5 FIXED G12
90
RIPPLE REJECTION (dB)
RIPPLE REJECTION (dB)
60
40
–2.0
–50 –25
1.0
100
80
50
–1.0
LT1083/4/5-12 Ripple Rejection
vs Current
VRIPPLE
≤ 0.5VP-P
70
0
1083/4/5 FIXED G11
LT1083/4/5-12 Ripple Rejection
VRIPPLE ≤ 3VP-P
1.0
10
1083/4/5 FIXED G10
80
Temperature Stability
100
OUTPUT VOLTAGE CHANGE (%)
80
LT1083CP
LT1083CK
0
50 60 70 80 90 100 110 120 130 140 150
CASE TEMPERATURE (°C)
* AS LIMITED BY MAXIMUM JUNCTION TEMPERATURE
LT1083/4/5 FIXED G15
LT1084 Maximum Power
Dissipation*
LT1085 Maximum Power
Dissipation*
60
50
50
40
LT1084MK
30
20
10
LT1084CT
LT1084CP
30
20
LT1085MK
LT1085CT
10
LT1084CK
LT1085CK
0
50 60 70 80 90 100 110 120 130 140 150
CASE TEMPERATURE (°C)
* AS LIMITED BY MAXIMUM JUNCTION TEMPERATURE
LT1083/4/5 FIXED G16
8
POWER (W)
POWER (W)
40
0
50 60 70 80 90 100 110 120 130 140 150
CASE TEMPERATURE (°C)
* AS LIMITED BY MAXIMUM JUNCTION TEMPERATURE
LT1083/4/5 FIXED G17
1083ffe
For more information www.linear.com/LT1083
LT1083/LT1084/LT1085 Fixed
Block Diagram
VIN
+
–
THERMAL
LIMIT
VOUT
GND
LT1083/4/5 BD
Applications Information
The LT1083 family of three-terminal regulators are easy
to use and have all the protection features that are expected in high performance voltage regulators. They are
short circuit protected, have safe area protection as well
as thermal shutdown to turn off the regulator should the
temperature exceed about 165°C.
These regulators offer lower dropout voltage and more
precise reference tolerance. Further, the reference stability
with temperature is improved over older types of regulators. The only circuit difference between using the LT1083
family and older regulators is that they require an output
capacitor for stability.
Stability
The circuit design used in the LT1083 family requires the
use of an output capacitor as part of the device frequency
compensation. For all operating conditions, the addition
of 150µF aluminum electrolytic or a 22µF solid tantalum
on the output will ensure stability. Normally capacitors
much smaller than this can be used with the LT1083.
Many different types of capacitors with widely varying
characteristics are available. These capacitors differ in
capacitor tolerance (sometimes ranging up to ±100%),
equivalent series resistance, and capacitance temperature
coefficient. The 150µF or 22µF values given will ensure
stability.
Normally, capacitor values on the order of 100µF are used
in the output of many regulators to ensure good transient
response with heavy load current changes. Output capacitance can be increased without limit and larger values of
output capacitance further improve stability and transient
response of the LT1083 regulators.
Another possible stability problem that can occur in monolithic IC regulators is current limit oscillations. These can
occur because in current limit the safe area protection
exhibits a negative impedance. The safe area protection
decreases the current limit as the input-to-output voltage increases.That is the equivalent of having a negative
1083ffe
For more information www.linear.com/LT1083
9
LT1083/LT1084/LT1085 Fixed
applications information
resistance since increasing voltage causes current to
decrease. Negative resistance during current limit is not
unique to the LT1083 series and has been present on all
power IC regulators. The value of negative resistance is
a function of how fast the current limit is folded back as
input-to-output voltage increases. This negative resistance
can react with capacitors or inductors on the input to
cause oscillations during current limiting. Depending on
the value of series resistance, the overall circuitry may
end up unstable. Since this is a system problem, it is not
necessarily easy to solve; however it does not cause any
problems with the IC regulator and can usually be ignored.
Protection Diodes
In normal operation the LT1083 family does not need any
protection diodes, The internal diode between the input
and the output pins of the LT1083 family can handle
microsecond surge currents of 50A to 100A. Even with
large output capacitances it is very difficult to get those
values of surge current in normal operation. Only with
high value output capacitors, such as 1000µF to 5000µF
and with the input pin instantaneously shorted to ground,
can damage occur. A crowbar circuit at the input of the
LT1083 can generate those kinds of currents and a diode
from output-to-input is then recommended. Normal
power supply cycling or even plugging and unplugging
in the system will not generate currents large enough to
do any damage.
D1
1N4002
(OPTIONAL)
VIN
IN
LT1083
ADJ
OUT
VOUT
+
COUT
150µF
Overload Recovery
Like any of the IC power regulators, the LT1083 has safe
area protection. The safe area protection decreases the
current limit as input-to-output voltage increases and keeps
the power transistor inside a safe operating region for all
values of input-to-output voltage. The LT1083 protection
is designed to provide some output current at all values
of input-to-output voltage up to the device breakdown.
When power is first turned on, as the input voltage rises,
the output follows the input, allowing the regulator to start
up into very heavy loads. During the start-up, as the input
voltage is rising, the input-to-output voltage differential
remains small allowing the regulator to supply large
output currents. With high input voltage a problem can
occur wherein removal of an output short will not allow
the output voltage to recover. Older regulators such as
the 7800 series, also exhibited this phenomenon so it is
not unique to the LT1083.
The problem occurs with a heavy output load when the
input voltage is high and the output voltage is low, such
as immediately after a removal of a short. The load line for
such a load may intersect the output current curve at two
points. If this happens there are two stable output operating points for the regulator. With this double intersection
the power supply may need to be cycled down to zero and
brought up again to make the output recover.
Ripple Rejection
In applications that require improved ripple rejection the
LT1083 series adjustable regulators should be used. With
LT1083 series adjustable regulators the addition of a bypass capacitor from the adjust pin to ground will reduce
output ripple by the ratio of VOUT/1.25V. See LT1083 series
adjustable regulator data sheet.
1083/4/5 AI01
10
1083ffe
For more information www.linear.com/LT1083
LT1083/LT1084/LT1085 Fixed
applications information
Load Regulation
Because the LT1083 is a three-terminal device, it is not possible to provide true remote load sensing. Load regulation
will not be limited by the resistance of the wire connecting the regulator to the load. The data sheet specification
for the load regulation is measured at the bottom of the
package. Negative side sensing is a true Kelvin connection,
with the ground pin of the device returned to the negative
side of the load.
Thermal Considerations
The LT1083 series of regulators have internal power and
thermal limiting circuitry designed to protect the device
under overload conditions. For continuous normal load
conditions however, maximum junction temperature
ratings must not be exceeded. It is important to give
careful consideration to all sources of thermal resistance
from junction to ambient. This includes junction-to-case,
case- to-heat sink interface, and heat sink resistance itself.
New thermal resistance specifications have been developed
to more accurately reflect device temperature and ensure
safe operating temperatures. The data section for these
new regulators provides a separate thermal resistance and
maximum junction temperature for both the Control Section
and the Power Section. Previous regulators, with a single
junction-to-case thermal resistance specification, used
an average of the two values provided here and therefore
could allow excessive junction temperatures under certain
conditions of ambient temperature and heat sink resistance.
To avoid this possibility, calculations should be made for
both sections to ensure that both thermal limits are met.
Junction-to-case thermal resistance is specified from
the IC junction to the bottom of the case directly below
the die. This is the lowest resistance path for heat flow.
Proper mounting is required to ensure the best possible
thermal flow from this area of the package to the heat sink.
Thermal compound at the case-to-heat sink interface is
strongly recommended. If the case of the device must
be electronically isolated, a thermally conductive spacer
can be used as long as its added contribution to thermal
resistance is considered. Note that the case of all devices
in this series is electronically connected to the output.
For example, using a LT1083-5CP (TO-3P, Commercial)
and assuming:
VIN(max continuous) = 9V, VOUT = 5V, IOUT = 6A,
TA = 75°C, θHEAT SINK = 1°C/W,
θCASE-TO-HEAT SINK = 0.2°C/W for P package with
thermal compound.
Power dissipation under these conditions is equal to:
PD = (VIN – VOUT) (IOUT) = 24W
Junction temperature will be equal to:
TJ = TA + PD (θ HEAT SINK + θCASE-TO-HEAT SINK + θJC)
For the Control Section:
TJ = 75°C + 24W (1°C/W + 0.2°C/W + 0.5°C/W) =
118°C
118°C < 125°C = TJMAX (Control Section Commer cial Range)
For the Power Transistor:
TJ = 75°C + 24W (1°C/W + 0.2°C/W + 1.6°C/W)=
142°C
142°C < 150°C = TJMAX (Power Transistor Commer cial Range)
In both cases the junction temperature is below the maximum rating for the respective sections, ensuring reliable
operation.
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For more information www.linear.com/LT1083
11
LT1083/LT1084/LT1085 Fixed
Typical Applications
High Efficiency Regulator
Paralleling Regulators
1mH
28V
INPUT
10,000µF
10k
IN
+
OUTPUT
LT1083-5 OUT
VIN
IN
2 FEET #18 WIRE*
LT1083-5 OUT
GND
GND
470Ω
MR1122
VOUT = 5V
IOUT = 0A TO 15A
0.015Ω
1N914
28V
IN
LT1083-5 OUT
*THE #18 WIRE ACTS
AS BALLAST RESISTANCE
INSURING CURRENT SHARING
BETWEEN BOTH DEVICES
GND
1k
1M
4N28
LT1083/4/5 TA04
10k
+
LT1011
LT1083/4/5 TA03
10k
–
28V
1N914
7.5A Regulator
T1
TRIAD
F-269U
L
1mH
C30B
20Ω
3
110VAC
20Ω
T2
1N4003
4
IN
+ C1
LT1083-12 OUT
GND
50,000µF
+
12V
0A TO 7.5A
100µF
2
1
LT1004-1.2
C30B
1N4003
1N4003
1N914
1µF
82k
16k*
560Ω
15k
15V
2
8
–15V
4
+
3
–
0.1µF
1
1N4148
7
8
100pF
–
2N3904
3
1
8
LT1011
1
+
10k
2
15k
REGULATOR WITH SCR PREREGULATOR TO
LOWER POWER DISSIPATION. ABOUT 1.7V
DIFFERENTIAL IS MAINTAINED ACROSS THE
LT1083 INDEPENDENT OF LOAD CURRENT.
12
NC
15V
–15V
4
* 1% FILM RESISTOR
L-DALE TO-5 TYPE
T2-STANCOR 11Z-2003
11k*
200k
7
LT1011
10k
16k*
15V
6
+
3
LM301A
7
15V
–
4
–15V
2
11k*
LT1083/4/5 TA05
1µF
1083ffe
For more information www.linear.com/LT1083
LT1083/LT1084/LT1085 Fixed
Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
K Package
2-Lead TO-3 Metal Can
(LTC DWG # 05-08-1310)
.760 – .775
(19.30 – 19.69)
.320 – .350
(8.13 – 8.89)
.060 – .135
(1.524 – 3.429)
.420 – .480
(10.67 – 12.19)
.038 – .043
(0.965 – 1.09)
1.177 – 1.197
(29.90 – 30.40)
.655 – .675
(16.64 – 17.15)
.210 – .220
(5.33 – 5.59)
.425 – .435
(10.80 – 11.05)
.151 – .161
(3.86 – 4.09)
DIA, 2PLCS
.167 – .177
(4.24 – 4.49)
R
.067 – .077
(1.70 – 1.96)
.490 – .510
(12.45 – 12.95)
R
K2 (TO-3) 0801
OBSOLETE PACKAGE
1083ffe
For more information www.linear.com/LT1083
13
LT1083/LT1084/LT1085 Fixed
Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
T Package
3-Lead Plastic TO-220
T Package
(LTC DWG # 05-08-1420)
3-Lead Plastic TO-220
(Reference LTC DWG # 05-08-1420)
.147 – .155
(3.734 – 3.937)
DIA
.390 – .415
(9.906 – 10.541)
.165 – .180
(4.191 – 4.572)
.045 – .055
(1.143 – 1.397)
.230 – .270
(5.842 – 6.858)
.460 – .500
(11.684 – 12.700)
.570 – .620
(14.478 – 15.748)
.330 – .370
(8.382 – 9.398)
.980 – 1.070
(24.892 – 27.178)
.520 – .570
(13.208 – 14.478)
.100
(2.540)
BSC
14
.028 – .038
(0.711 – 0.965)
.218 – .252
(5.537 – 6.401)
.050
(1.270)
TYP
.013 – .023
(0.330 – 0.584)
.095 – .115
(2.413 – 2.921)
T3 (TO-220) 0801
1083ffe
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LT1083/LT1084/LT1085 Fixed
Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
M Package
M Package
3-Lead
Plastic DD Pak
3-Lead
DD Pak
(LTC
DWG Plastic
# 05-08-1460
Rev F)
(Reference LTC DWG # 05-08-1460 Rev F)
.256
(6.502)
.060
(1.524)
TYP
.060
(1.524)
.390 – .415
(9.906 – 10.541)
.165 – .180
(4.191 – 4.572)
.045 – .055
(1.143 – 1.397)
15°
.060
(1.524)
.183
(4.648)
.330 – .370
(8.382 – 9.398)
+.008
.004 –.004
+0.203
0.102 –0.102
(
.059
(1.499)
)
.095 – .115
(2.413 – 2.921)
.075
(1.905)
.300
(7.620)
+.012
.143 –.020
+0.305
3.632 –0.508
(
BOTTOM VIEW OF DD PAK
HATCHED AREA IS SOLDER PLATED
COPPER HEAT SINK
)
DETAIL A
.050
(1.270)
.100
(2.54)
BSC
.013 – .023
(0.330 – 0.584)
.050 ±.012
(1.270 ±0.305)
DETAIL A
0° – 7° TYP
.420
.080
.420
.350
0° – 7° TYP
.276
.325
.205
.585
.585
.320
.090
.100
.090
.100
.070
RECOMMENDED SOLDER PAD LAYOUT
NOTE:
1. DIMENSIONS IN INCH/(MILLIMETER)
2. DRAWING NOT TO SCALE
.070
M (DD3) 0212 REV F
RECOMMENDED SOLDER PAD LAYOUT
FOR THICKER SOLDER PASTE APPLICATIONS
1083ffe
For more information www.linear.com/LT1083
15
LT1083/LT1084/LT1085 Fixed
Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
P Package
P Package
3-Lead Plastic TO-3P
(Similar to TO-247)
3-Lead
Plastic
(Similar
(LTC
DWG #TO-3P
05-08-1450
RevtoA)TO-247))
(Reference LTC DWG # 05-08-1450 Rev A)
.515 – .580
(13.08 – 14.73)
.305 – .370
(7.75 – 9.40)
.560 – .620
(14.22 – 15.75)
.187 – .207
(4.75 – 5.26)
.620 – .640
(15.75 – 16.26)
.265 – .293
(6.73 – 7.44)
MOUNTING HOLE
18° – 22°
.115 – .145
(2.92 – 3.68)
DIA
.819 – .870
(20.80 – 22.10)
.060 – .081
(1.52 – 2.06)
.170 – .215
(4.32 – 5.46)
.635 – .720
(16.13 – 18.29)
EJECTOR PIN MARKS
.105 – .125
(2.67 – 3.18)
DIA
.580 – .600
(14.73 – 15.24)
3° – 7°
.104 – .145
(2.64 – 3.68)
.170
(4.32)
MAX
.780 – .800
(19.81 – 20.32)
.042 – .052
(1.07 – 1.32)
BOTTOM VIEW OF TO-3P
HATCHED AREA IS SOLDER PLATED
COPPER HEAT SINK
NOTE:
1. DIMENSIONS IN INCH/(MILLIMETER)
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED .030" (.762mm)
.074 – .084
(1.88 – 2.13)
.215
(5.46)
BSC
.113 – .123
(2.87 – 3.12)
.087 – .102
(2.21 – 2.59)
.020 – .040
(0.51 – 1.02)
P3 0512 REV A
OBSOLETE PACKAGE
16
1083ffe
For more information www.linear.com/LT1083
LT1083/LT1084/LT1085 Fixed
Revision History
(Revision history begins at Rev E)
REV
DATE
DESCRIPTION
E
06/15
Obsolete TO-3P package.
PAGE NUMBER
2, 16
1083ffe
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection
of its circuits
as described
herein will not infringe on existing patent rights.
For more
information
www.linear.com/LT1083
17
LT1083/LT1084/LT1085 Fixed
Typical Application
Adjusting Output Voltage
VIN > 12V
LT1085-5
+
+
10µF
+
Regulator with Reference
VIN > 11.5V
5V to 10V
100µF
LT1085-5
+
+
10µF
10V
100µF
5VOUT
LT1029
1k
10µF*
LT1083/4/5 TA07
LT1083/4/5 TA06
*OPTIONAL IMPROVES RIPPLE REJECTION
Low Dropout Negative Supply
Battery Backed Up Regulated Supply
VIN
IN
VIN
+
LT1084-12 OUT
GND
+
+
10,000µF
10µF
50Ω
SELECT
FOR
CHARGE
RATE
100µF
LT1083/4/5 TA08
FLOATING INPUT
5.2V LINE
5.0V BATTERY
LT1084-5
VOUT = –12V
LT1084-5
6.5V
+
10µF
+
100µF
LT1083/4/5 TA09
Related Parts
PART NUMBER
DESCRIPTION
COMMENTS
LT1129
LT1175
LT1185
LT1529
LT1580
LT1581
LT1584/LT1585/
LT1587
700mA Micropower Low Dropout Regulator
500mA Negative Low Dropout Micropower Regulator
3A Negative Low Dropout Regulator
3A Low Dropout Regulator with 50µA IQ
7A, Very Low Dropout Regulator
10A, Very Low Dropout Regulator
7A/4.6A/3A Fast Response LDOs
50µA Quiescent Current
45µA IQ, 0.26V Dropout Voltage, SOT-223 Package
VIN: –4.5V to –35V, 0.8V Dropout Voltage, DD-Pak and TO-220 Packages
500mV Dropout Voltage
0.54V Dropout at 7A, Fixed 2.5VOUT and Adjustable
0.63V Dropout at 10A, Fixed 2.5VOUT and Adjustable
Fast Transient Response for Microprocessor Applications
LT1761 Series
100mA, Low Noise, Low Dropout Micropower Regulators
in SOT-23
150mA, Low Noise, LDO Micropower Regulators
500mA, Low Noise LDO Micropower Regulators
3A Low Noise Fast Transient Response LDO
300mA, Low Noise LDO Micropower Regulator
1.5A, Low Noise, Fast Transient Response LDO
200mA, Low Noise, Negative LDO
20µA Quiescent Current, 20µVRMS Noise, SOT-23 Package
LT1762 Series
LT1763 Series
LT1764
LT1962
LT1963
LT1964
LT3015
LT3080/
LT3080-1
LT3090
25µA Quiescent Current, 20µVRMS Noise, MSOP Package
30µA Quiescent Current, 20µVRMS Noise, SO-8 Package
40µVRMS Noise, 5-Lead DD Package
20µVRMS Noise, MSOP Package
40µVRMS Noise, SOT-223 Package
340mV Dropout Voltage, Low Noise 30µVRMS, VIN = –1.8V to –20V, ThinSOT™
and 3mm × 3mm DFN-8 Packages
1.5A, Low Noise, Negative Linear Regulator with Precision
VIN: –1.8V to –30V, VOUT: –1.22V to –29.5V, Dropout Voltage: 310mV, Precision
Current Limit
Current Limit with Foldback, Low Output Noise: 60μVRMS (10Hz to 100kHz),
TO-220, DD-Pak, DFN and MSOP Packages
1.1A, Parallelable, Low Noise, Low Dropout Linear Regulator 300mV Dropout Voltage (2-Supply Operation), Low Noise: 40µVRMS,
VIN: 1.2V to 36V, VOUT: 0V to 35.7V, Stable with Ceramic Caps, TO-220,
DD-Pak, SOT-223, MS8E and 3mm × 3mm DFN-8 Packages; "-1" Version Has
Integrated Internal Ballast Resistor
600mA Low Noise Negative LDO with Programmable ILIMIT 300mV Dropout Voltage, 18µVRMS Output Voltage Noise, Parallelable 50μA SET
Pin Current: ±1% Initial Accuracy, Positive/Negative Current Monitors Wide Input
Voltage Range: –1.5V to –36V, Rail-to-Rail Output Voltage Range: 0V to –32V
18 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/LT1083
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com/LT1083
1083ffe
LT 0615 REV E • PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 1994
工商网监
湘ICP备2023018690号
