LT3080
Adjustable1.1A Single
Resistor Low Dropout
Regulator
FEATURES
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DESCRIPTION
The LT
®
3080 is a 1.1A low dropout linear regulator that can
be paralleled to increase output current or spread heat in
surface mounted boards. Architected as a precision cur-
rent source and voltage follower allows this new regulator
to be used in many applications requiring high current,
adjustability to zero, and no heat sink. Also the device
brings out the collector of the pass transistor to allow low
dropout operation —down to 350 millivolts— when used
with multiple supplies.
A key feature of the LT3080 is the capability to supply a
wide output voltage range. By using a reference current
through a single resistor, the output voltage is programmed
to any level between zero and 36V. The LT3080 is stable
with 2.2μF of capacitance on the output, and the IC uses
small ceramic capacitors that do not require additional
ESR as is common with other regulators.
Internal protection circuitry includes current limiting and
thermal limiting. The LT3080 regulator is offered in the
8-lead MSOP (with an exposed pad for better thermal
characteristics), a 3mm
×
3mm DFN, 5-lead DD-Pak,
TO-220 and a simple-to-use 3-lead SOT-223 version.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and VLDO
and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
Outputs May be Paralleled for Higher Current and
Heat Spreading
Output Current: 1.1A
Single Resistor Programs Output Voltage
1% Initial Accuracy of SET Pin Current
Output Adjustable to 0V
Low Output Noise: 40μV
RMS
(10Hz to 100kHz)
Wide Input Voltage Range: 1.2V to 36V
Low Dropout Voltage: 350mV (Except SOT-223
Package)
<1mV Load Regulation
<0.001%/V Line Regulation
Minimum Load Current: 0.5mA
Stable with 2.2μF Minimum Ceramic Output Capacitor
Current Limit with Foldback and Overtemperature
Protected
Available in 8-Lead MSOP 3mm
×
3mm DFN,
,
5-Lead DD-Pak, TO-220 and 3-Lead SOT-223
APPLICATIONS
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High Current All Surface Mount Supply
High Efficiency Linear Regulator
Post Regulator for Switching Supplies
Low Parts Count Variable Voltage Supply
Low Output Voltage Power Supplies
TYPICAL APPLICATION
Variable Output Voltage 1.1A Supply
V
IN
1.2V TO 36V
IN
V
CONTROL
LT3080
Set Pin Current Distribution
N = 13792
1μF
SET
+
–
OUT
V
OUT
2.2μF
9.80
10.00
10.20
9.90
10.10
SET PIN CURRENT DISTRIBUTION (μA)
3080 G02
R
SET
V
OUT
= R
SET
• 10μA
3080 TA01a
3080fb
1
LT3080
ABSOLUTE MAXIMUM RATINGS
(Note 1)(All Voltages Relative to V
OUT
)
V
CONTROL
Pin Voltage ..................................... 40V, –0.3V
IN Pin Voltage ................................................ 40V, –0.3V
SET Pin Current (Note 7) .....................................±10mA
SET Pin Voltage (Relative to OUT) .........................±0.3V
Output Short-Circuit Duration .......................... Indefinite
Operating Junction Temperature Range
(Notes 2, 10) .......................................... –40°C to 125°C
Storage Temperature Range:.................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
MS8E, Q, T and ST Packages Only.................... 300°C
PIN CONFIGURATION
TOP VIEW
FRONT VIEW
OUT 1
OUT 2
OUT 3
SET 4
9
8
7
6
5
IN
IN
NC
V
CONTROL
TOP VIEW
OUT
OUT
OUT
SET
1
2
3
4
8
7
6
5
IN
IN
NC
V
CONTROL
5
4
TAB IS
OUT
3
2
1
Q PACKAGE
5-LEAD PLASTIC DD-PAK
T
JMAX
= 125°C,
θ
JA
= 30°C/W,
θ
JC
= 3°C/W
IN
V
CONTROL
OUT
SET
NC
9
MS8E PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 60°C/W,
θ
JC
= 10°C/W
EXPOSED PAD (PIN 9) IS OUT, MUST BE SOLDERED TO PCB
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 64°C/W,
θ
JC
= 3°C/W
EXPOSED PAD (PIN 9) IS OUT, MUST BE SOLDERED TO PCB
FRONT VIEW
5
TAB IS
OUT
4
3
2
1
T PACKAGE
5-LEAD PLASTIC TO-220
FRONT VIEW
IN
V
CONTROL
OUT
SET
NC
ST PACKAGE
3-LEAD PLASTIC SOT-223
*IN IS V
CONTROL
AND IN TIED TOGETHER
T
JMAX
= 125°C,
θ
JA
= 55°C/W,
θ
JC
= 15°C/W
TAB IS
OUT
3
2
1
IN*
OUT
SET
T
JMAX
= 125°C,
θ
JA
= 40°C/W,
θ
JC
= 3°C/W
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
LT3080EDD#PBF
LT3080EDD#TRPBF
LCBN
LT3080EMS8E#PBF
LT3080EMS8E#TRPBF
LTCBM
LT3080EQ#PBF
LT3080EQ#TRPBF
LT3080EQ
LT3080ET#PBF
LT3080ET#TRPBF
LT3080ET
LT3080EST#PBF
LT3080EST#TRPBF
3080
LEAD BASED FINISH
TAPE AND REEL
PART MARKING
LT3080EDD
LT3080EDD#TR
LCBN
LT3080EMS8E
LT3080EMS8E#TR
LTCBM
LT3080EQ
LT3080EQ#TR
LT3080EQ
LT3080ET
LT3080ET#TR
LT3080ET
LT3080EST
LT3080EST#TR
3080
Consult LTC Marketing for parts specified with wider operating temperature ranges.
PACKAGE DESCRIPTION
8-Lead (3mm × 3mm) Plastic DFN
8-Lead Plastic MSOP
5-Lead Plastic DD-Pak
5-Lead Plastic TO-220
3-Lead Plastic SOT-223
PACKAGE DESCRIPTION
8-Lead (3mm × 3mm) Plastic DFN
8-Lead Plastic MSOP
5-Lead Plastic DD-Pak
5-Lead Plastic TO-220
3-Lead Plastic SOT-223
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
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/
3080fb
2
LT3080
ELECTRICAL CHARACTERISTICS
PARAMETER
SET Pin Current
Output Offset Voltage (V
OUT
– V
SET
)
V
IN
= 1V, V
CONTROL
= 2V, I
OUT
= 1mA
CONDITIONS
I
SET
V
IN
= 1V, V
CONTROL
= 2.0V, I
LOAD
= 1mA, T
J
= 25°C
V
IN
≥ 1V, V
CONTROL
≥ 2.0V, 1mA ≤ I
LOAD
≤ 1.1A (Note 9)
V
OS
DFN and MSOP Package
SOT-223, DD-Pak and T0-220 Package
Load Regulation
Line Regulation (Note 9)
DFN and MSOP Package
Line Regulation (Note 9)
SOT-223, DD-Pak and T0-220 Package
Minimum Load Current (Notes 3, 9)
ΔI
SET
ΔI
LOAD
= 1mA to 1.1A
ΔV
OS
ΔI
LOAD
= 1mA to 1.1A (Note 8)
ΔI
SET
V
IN
= 1V to 25V, V
CONTROL
= 2V to 25V, I
LOAD
= 1mA
ΔV
OS
V
IN
= 1V to 25V, V
CONTROL
= 2V to 25V, I
LOAD
= 1mA
ΔI
SET
V
IN
= 1V to 26V, V
CONTROL
= 2V to 26V, I
LOAD
= 1mA
ΔV
OS
V
IN
= 1V to 26V, V
CONTROL
= 2V to 26V, I
LOAD
= 1mA
V
IN
= V
CONTROL
= 10V
V
IN
= V
CONTROL
= 25V (DFN and MSOP Package)
V
IN
= V
CONTROL
= 26V (SOT-223, DD-Pak and T0-220 Package)
I
LOAD
= 100mA
I
LOAD
= 1.1A
I
LOAD
= 100mA
I
LOAD
= 1.1A
I
LOAD
= 100mA
I
LOAD
= 1.1A
V
IN
= 5V, V
CONTROL
= 5V, V
SET
= 0V, V
OUT
= –0.1V
I
LOAD
= 1.1A, 10Hz ≤ f ≤ 100kHz, C
OUT
= 10μF, C
SET
= 0.1μF
10Hz ≤ f ≤ 100kHz
f = 120Hz, V
RIPPLE
= 0.5V
P-P
, I
LOAD
= 0.2A, C
SET
= 0.1μF, C
OUT
= 2.2μF
f = 10kHz
f = 1MHz
10ms Pulse
l
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l
l
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 11)
MIN
9.90
9.80
–2
–3.5
–5
–6
–0.1
0.6
0.1
0.003
0.1
0.003
300
TYP
10
10
MAX
10.10
10.20
2
3.5
5
6
1.3
0.5
0.5
500
1
1
1.6
200
500
6
30
UNITS
μA
μA
mV
mV
mV
mV
nA
mV
nA/V
mV/V
nA/V
mV/V
μA
mA
mA
V
V
mV
mV
mA
mA
A
μV
RMS
nA
RMS
dB
dB
dB
%/W
V
CONTROL
Dropout Voltage (Note 4)
V
IN
Dropout Voltage (Note 4)
V
CONTROL
Pin Current
Current Limit
Error Amplifier RMS Output Noise (Note 6)
Reference Current RMS Output Noise (Note 6)
Ripple Rejection
1.2
1.35
100
350
4
17
1.1
1.4
40
1
75
55
20
0.003
Thermal Regulation, I
SET
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:
Unless otherwise specified, all voltages are with respect to V
OUT
.
The LT3080 is tested and specified under pulse load conditions such that
T
J
≈ T
A
. The LT3080 E-Grade is 100% tested at T
A
= 25°C. Performance at
–40°C and 125°C is assured by design, characterization and correlation
with statistical process controls.
Note 3:
Minimum load current is equivalent to the quiescent current of
the part. Since all quiescent and drive current is delivered to the output
of the part, the minimum load current is the minimum current required to
maintain regulation.
Note 4:
For the LT3080, dropout is caused by either minimum control
voltage (V
CONTROL
) or minimum input voltage (V
IN
). Both parameters are
specified with respect to the output voltage. The specifications represent the
minimum input-to-output differential voltage required to maintain regulation.
Note 5:
The V
CONTROL
pin current is the drive current required for the
output transistor. This current will track output current with roughly a 1:60
ratio. The minimum value is equal to the quiescent current of the device.
Note 6:
Output noise is lowered by adding a small capacitor across the
voltage setting resistor. Adding this capacitor bypasses the voltage setting
resistor shot noise and reference current noise; output noise is then equal
to error amplifier noise (see Applications Information section).
Note 7:
SET pin is clamped to the output with diodes. These diodes only
carry current under transient overloads.
Note 8:
Load regulation is Kelvin sensed at the package.
Note 9:
Current limit may decrease to zero at input-to-output differential
voltages (V
IN
–V
OUT
) greater than 25V (DFN and MSOP package) or 26V
(SOT-223, DD-Pak and T0-220 Package). Operation at voltages for both IN
and V
CONTROL
is allowed up to a maximum of 36V as long as the difference
between input and output voltage is below the specified differential
(V
IN
–V
OUT
) voltage. Line and load regulation specifications are not
applicable when the device is in current limit.
Note 10:
This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed the maximum operating junction temperature
when overtemperature protection is active. Continuous operation above
the specified maximum operating junction temperature may impair device
reliability.
Note 11:
The SOT-223 package connects the IN and V
CONTROL
pins
together internally. Therefore, test conditions for this pin follow the
V
CONTROL
conditions listed in the Electrical Characteristics Table.
3080fb
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LT3080
TYPICAL PERFORMANCE CHARACTERISTICS
Set Pin Current
10.20
10.15
SET PIN CURRENT (μA)
10.10
10.05
10.00
9.95
9.90
9.85
9.80
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
3080 G01
Set Pin Current Distribution
2.0
N = 13792
OFFSET VOLTAGE (mV)
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
9.80
10.00
10.20
9.90
10.10
SET PIN CURRENT DISTRIBUTION (μA)
3080 G02
Offset Voltage (V
OUT
– V
SET
)
I
L
= 1mA
–2.0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
3080 G03
Offset Voltage Distribution
1.00
N = 13250
OFFSET VOLTAGE (mV)
0.75
Offset Voltage
I
LOAD
= 1mA
0.50
0.25
0
–0.25
–0.50
–0.75
–1.00
0.25
0
OFFSET VOLTAGE (mV)
–0.25
–0.50
Offset Voltage
T
J
= 25°C
T
J
= 125°C
–0.75
–1.00
–1.25
–1.50
–2
0
–1
1
V
OS
DISTRIBUTION (mV)
2
3080 G04
0
24
30
18
INPUT-TO-OUTPUT VOLTAGE (V)
*SEE NOTE 9 IN ELECTRICAL
CHARACTERISTICS TABLE
6
12
36*
3080 G05
–1.75
0
0.2
0.4
0.8
0.6
LOAD CURRENT (A)
1.0
1.2
3080 G06
Load Regulation
CHANGE IN OFFSET VOLTAGE WITH LOAD (mV)
0
–0.1
–0.2
–0.3
–0.4
–0.5
–0.6
–0.7
–0.8
–50 –25
0
CHANGE IN OFFSET VOLTAGE
(V
OUT
– V
SET
)
ΔI
LOAD
= 1mA TO 1.1A
V
IN
– V
OUT
= 2V
CHANGE IN REFERENCE CURRENT
20
10
0
–10
–20
–30
–40
–50
–60
25 50 75 100 125 150
TEMPERATURE (°C)
3080 G07
Minimum Load Current
0.8
MINIMUM IN VOLTAGE (V
IN
– V
OUT
) (mV)
MINIMUM LOAD CURRENT (mA)
0.7
0.6
0.5
0.4
V
IN, CONTROL
– V
OUT
= 1.5V
0.3
0.2
0.1
0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
3080 G08
Dropout Voltage
(Minimum IN Voltage)
400
350
T
J
= 125°C
300
250
200
150
100
50
0
0
0.2
0.8
0.6
OUTPUT CURRENT (A)
0.4
1.0
1.2
3080 G09
CHANGE IN REFERENCE CURRENT WITH LOAD (nA)
V
IN, CONTROL
– V
OUT
= 36V*
T
J
= 25°C
*SEE NOTE 9 IN ELECTRICAL
CHARACTERISTICS TABLE
3080fb
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LT3080
TYPICAL PERFORMANCE CHARACTERISTICS
MINIMUM CONTROL VOLTAGE (V
CONTROL
– V
OUT
) (V)
400
MINIMUM IN VOLTAGE (V
IN
– V
OUT
) (mV)
350
300
250
200
150
100
50
0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
3080 G10
1.6
T
J
= –50°C
1.4
1.2
T
J
= 125°C
1.0
0.8
0.6
0.4
0.2
0
0
0.2
0.8
0.6
OUTPUT CURRENT (A)
0.4
1.0
1.2
3080 G11
MINIMUM CONTROL VOLTAGE (V
CONTROL
– V
OUT
) (V)
Dropout Voltage
(Minimum IN Voltage)
Dropout Voltage (Minimum
V
CONTROL
Pin Voltage)
Dropout Voltage (Minimum
V
CONTROL
Pin Voltage)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
3080 G12
I
LOAD
= 1.1A
I
LOAD
= 1.1A
I
LOAD
= 500mA
T
J
= 25°C
I
LOAD
= 1mA
I
LOAD
= 100mA
Current Limit
1.6
1.4
CURRENT LIMIT (A)
CURRENT LIMIT (A)
1.2
1.0
0.8
0.6
0.4
0.2
V
IN
= 7V
V
OUT
= 0V
0
25 50 75 100 125 150
TEMPERATURE (°C)
3080 G13
Current Limit
1.6
1.4
1.2
1.0
0.8
LOAD CURRENT (mA)
0.6
0.4
0.2
0
0
24
30
18
INPUT-TO-OUTPUT DIFFERENTIAL (V)
6
12
36*
MSOP
AND
DFN
SOT-223, DD-PAK
AND TO-220
OUTPUT VOLTAGE
DEVIATION (mV)
T
J
= 25°C
75
50
25
0
–25
–50
400
300
200
100
0
Load Transient Response
V
OUT
= 1.5V
C
SET
= 0.1μF
V
IN
= V
CONTROL
= 3V
C
OUT
= 10μF CERAMIC
C
OUT
= 2.2μF CERAMIC
0
–50 –25
0
5
10 15 20 25 30 35 40 45 50
TIME (μs)
3080 G15
*SEE NOTE 9 IN ELECTRICAL
CHARACTERISTICS TABLE
3080 G14
Load Transient Response
150
OUTPUT VOLTAGE
DEVIATION (mV)
OUTPUT VOLTAGE
DEVIATION (mV)
100
50
0
–50
75
50
25
0
–25
–50
6
5
4
3
2
Line Transient Response
INPUT VOLTAGE (V)
5
4
3
2
1
0
OUTPUT VOLTAGE (V)
2.0
1.5
1.0
0.5
0
Turn-On Response
LOAD CURRENT (A)
1.2
0.9
0.6
0.3
0
0
5
V
IN
= V
CONTROL
= 3V
V
OUT
= 1.5V
C
OUT
= 10μF CERAMIC
C
SET
= 0.1μF
IN/CONTROL VOLTAGE (V)
–100
V
OUT
= 1.5V
I
LOAD
= 10mA
C
OUT
= 2.2μF
CERAMIC
C
SET
= 0.1μF
CERAMIC
R
SET
= 100k
C
SET
= 0
R
LOAD
= 1Ω
C
OUT
= 2.2μF CERAMIC
10 15 20 25 30 35 40 45 50
TIME (μs)
3080 G16
0
10 20 30 40 50 60 70 80 90 100
TIME (μs)
3080 G17
0
1
2
3
4 5 6
TIME (μs)
7
8
9
10
3080 G27
3080fb
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