LT3092
200mA 2-Terminal
Programmable Current Source
FEATURES
n
Programmable 2-Terminal Current Source
n
Maximum Output Current: 200mA
n
Wide Input Voltage Range: 1.2V to 40V
n
Input/Output Capacitors Not Required
n
Resistor Ratio Sets Output Current
n
Initial Set Pin Current Accuracy: 1%
n
Reverse-Voltage Protection
n
Reverse-Current Protection
n
<0.001%/V Line Regulation Typical
n
Current Limit and Thermal Shutdown Protection
n
Available in 8-Lead SOT-23, 3-Lead SOT-223 and
8-Lead 3mm × 3mm DFN Packages
APPLICATIONS
n
2-Terminal Floating Current Source
n
GND Referred Current Source
n
Variable Current Source
n
In-Line Limiter
n
Intrinsic Safety Circuits
DESCRIPTION
The LT®3092 is a programmable 2-terminal current
source. It requires only two resistors to set an output
current between 0.5mA and 200mA. A multitude of analog
techniques lend themselves to actively programming the
output current. The LT3092 is stable without input and
output capacitors, offering high DC and AC impedance. This
feature allows operation in intrinsically safe applications.
The SET pin features 1% initial accuracy and low temperature coeffi cient. Current regulation is better than
10ppm/V from 1.5V to 40V.
The LT3092 can operate in a 2-terminal current source
confi guration in series with signal lines. It is ideal for driving sensors, remote supplies, and as a precision current
limiter for local supplies.
Internal protection circuitry includes reverse-battery and
reverse-current protection, current limiting and thermal
limiting. The LT3092 is offered in the 8-lead TSOT-23,
3-lead SOT-223 and 8-lead 3mm × 3mm DFN packages.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Adjustable 2-Terminal Current Source
VIN – V
LT3092
IµA
SOURCE
= 1.2V TO 40V
OUT
IN
10µA
+
–
SET OUT
R
SET
= 10 •
R
R
SET
R
OUT
OUT
3092 TA01a
SET Pin Current vs Temperature
10.100
10.075
10.050
10.025
10.000
9.975
SET PIN CURRENT (µA)
9.950
9.925
9.900
–50
–25
25 50 10075 125
0
TEMPERATURE (°C)
150
3092 TA01b
3092fb
1
LT3092
ABSOLUTE MAXIMUM RATINGS
(Note 1) All Voltages Relative to V
IN Pin Voltage Relative to SET, OUT ........................±40V
SET Pin Current (Note 6) .....................................±15mA
SET Pin Voltage (Relative to OUT, Note 6) ...............±10V
Output Short-Circuit Duration .......................... Indefi nite
PIN CONFIGURATION
TOP VIEW
1OUT
OUT
2
NC
3
SET
4
8-LEAD (3mm s 3mm) PLASTIC DFN
T
= 125°C, θJA = 28°C/W, θJC = 10°C/W
JMAX
EXPOSED PAD (PIN 9) IS OUT, MUST BE SOLDERED TO OUT
ON THE PCB. SEE THE APPLICATIONS INFORMATION SECTION.
9
DD PACKAGE
8
IN
IN
7
NC
6
NC
5
TAB IS OUT
T
= 125°C, θJA = 24°C/W, θJC = 15°C/W
JMAX
TAB IS OUT, MUST BE SOLDERED TO OUT ON THE PCB.
SEE THE APPLICATIONS INFORMATION SECTION.
OUT
Operating Junction Temperature Range (Notes 2, 8)
E, I Grades ......................................... –40°C to 125°C
MP Grade ........................................... –55°C to 125°C
Storage Temperature Range ................... –65°C to 150°C
Lead Temperature (ST, TS8 Packages Only)
Soldering, 10 sec .............................................. 300°C
TOP VIEW
3
2
1
ST PACKAGE
3-LEAD PLASTIC SOT-223
IN
OUT
SET
T
OUT 2
OUT 3
OUT 4
JMAX
TOP VIEW
NC 1
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
= 125°C, θJA = 57°C/W, θJC = 15°C/W
8 IN
7 IN
6 NC
5 SET
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT3092EDD#PBF LT3092EDD#TRPBF LFJD
LT3092IDD#PBF LT3092IDD#TRPBF LFJD
8-Lead (3mm × 3mm) Plastic DFN
8-Lead (3mm × 3mm) Plastic DFN
LT3092EST#PBF LT3092EST#TRPBF 3092 3-Lead Plastic SOT-223 –40°C to 125°C
LT3092IST#PBF LT3092IST#TRPBF 3092 3-Lead Plastic SOT-223 –40°C to 125°C
LT3092MPST#PBF LT3092MPST#TRPBF 3092MP 3-Lead Plastic SOT-223 –55°C to 125°C
LT3092ETS8#PBF LT3092ETS8#TRPBF LTFJW 8-Lead Plastic SOT-23 –40°C to 125°C
LT3092ITS8#PBF LT3092ITS8#TRPBF LTFJW 8-Lead Plastic SOT-23 –40°C to 125°C
LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT3092EDD LT3092EDD#TR LFJD
LT3092IDD LT3092IDD#TR LFJD
8-Lead (3mm × 3mm) Plastic DFN
8-Lead (3mm × 3mm) Plastic DFN
LT3092EST LT3092EST#TR 3092 3-Lead Plastic SOT-223 –40°C to 125°C
LT3092IST LT3092IST#TR 3092 3-Lead Plastic SOT-223 –40°C to 125°C
LT3092MPST LT3092MPST#TR 3092MP 3-Lead Plastic SOT-223 –55°C to 125°C
LT3092ETS8 LT3092ETS8#TR LTFJW 8-Lead Plastic SOT-23 –40°C to 125°C
LT3092ITS8 LT3092ITS8#TR LTFJW 8-Lead Plastic SOT-23 –40°C to 125°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container.
For more information on lead free part marking, go to:
For more information on tape and reel specifi cations, go to:
http://www.linear.com/leadfree/
http://www.linear.com/tapeandreel/
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
3092fb
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LT3092
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
PARAMETER CONDITIONS MIN TYP MAX UNITS
SET Pin Current I
Offset Voltage (V
OUT
– V
) V
SET
Current Regulation (Note 7) ∆I
∆V
Line Regulation ∆I
∆V
Minimum Load Current (Note 3) 2V ≤ V
Dropout Voltage (Note 4) I
Current Limit VIN = 5V, V
Reference Current RMS Output Noise (Note 5) 10Hz ≤ f ≤ 100kHz 0.7 nA
Ripple Rejection f = 120Hz, V
Thermal Regulation I
SET
OS
SET
OS
SET
OS
SET
= 25°C. (Note 2)
J
VIN = 2V, I
2V ≤ V
VIN = 2V, I
V
= 2V, I
IN
∆I
LOAD
∆I
LOAD
∆VIN = 2V to 40V, I
∆V
= 2V to 40V, I
IN
= 10mA
LOAD
I
= 200mA
LOAD
C
= 0.1µF, C
SET
f = 10kHz
f = 1MHz
= 1mA
LOAD
≤ 40V, 1mA ≤ I
IN
= 1mA
LOAD
= 1mA
LOAD
= 1mA to 200mA
= 1mA to 200mA
LOAD
LOAD
≤ 40V
IN
= 0V, V
SET
RIPPLE
OUT
OUT
= 0.5V
= 2.2µF
LOAD
= 1mA
= 1mA
= –0.1V
, I
P-P
≤ 200mA
= 0.1A,
LOAD
9.9
l
9.8
10
10
10.1
10.2
–2
l
–4
–0.1
l
l
l
l
l
200 300 mA
–0.5 –2
0.03
0.003
0.2
0.010
300 500 µA
1.22
1.3
1.45
1.65
90
75
20
µA
µA
2
4
mV
mV
nA
mV
nA/V
mV/V
RMS
dB
dB
dB
10ms Pulse 0.003 %/ W
V
V
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 specifi ed, all voltages are with respect to V
OUT
.
The LT3092E is tested and specifi ed under pulse load conditions such
that T
≅ TA. The LT3092E is 100% tested at TA = 25°C. Performance at
J
–40°C and 125°C is assured by design, characterization, and correlation
with statistical process controls. The LT3092I is guaranteed to meet all
data sheet specifi cations over the full –40°C to 125°C operating junction
temperature range. The LT3092MP is 100% tested and guaranteed over
the –55°C to 125°C operating junction temperature range.
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 LT3092, dropout is specifi ed as the minimum input-tooutput voltage differential required supplying a given output current.
Note 5: Adding a small capacitor across the reference current resistor
lowers output noise. Adding this capacitor bypasses the resistor shot noise
and reference current noise (see the Applications Information section).
Note 6: Diodes with series 1k resistors clamp the SET pin to the OUT pin.
These diodes and resistors only carry current under transient overloads.
Note 7: Current regulation is Kelvin-sensed at the package.
Note 8: This IC includes overtemperature protection that protects the
device during momentary overload conditions. Junction temperature
exceeds the maximum operating junction temperature when
overtemperature protection is active. Continuous operation above the
specifi ed maximum operating junction temperature may impair device
reliability.
3092fb
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LT3092
TYPICAL PERFORMANCE CHARACTERISTICS
SET Pin Current SET Pin Current Distribution
10.100
10.075
10.050
10.025
10.000
9.975
SET PIN CURRENT (μA)
9.950
9.925
9.900
–50
–25 25
0
50
TEMPERATURE (°C)
75
100
125
150
3092 G01
N = 1326
9.80
9.90
SET PIN CURRENT DISTRIBUTION (µA)
Offset Voltage Distribution
N = 1326
–2
–1
VOS DISTRIBUTION (mV)
0
1
2
3092 G04
10
10.10
Offset Voltage
1.00
I
OUT
0.75
0.50
0.25
0
–0.25
OFFSET VOLTAGE (mV)
–0.50
–0.75
–1.00
0
Offset Voltage (V
2.0
1.5
1.0
0.5
0.0
–0.5
OFFSET VOLTAGE (mV)
–1.0
–1.5
10.20
3092 G02
= 1mA
5
10
INPUT-TO-OUTPUT VOLTAGE (V)
–2.0
–50
–25
15 20 3025 35
– V
OUT
25 50 10075 125
0
TEMPERATURE (°C)
40
3092 G05
SET
)
150
3092 G03
4
Offset Voltage
100
50
0
–50
–100
–150
–200
–250
OFFSET VOLTAGE (μV)
–300
–350
–400
0
50 150 200
100
LOAD CURRENT (mA)
3092 G06
Current Regulation
20
∆I
= 1mA TO 200mA
OUT
10
– V
V
0
–10
–20
–30
–40
WITH LOAD (nA)
–50
–60
CHANGE IN REFERENCE CURRENT
–70
–80
–50
= 3V
IN
OUT
–25 25
0
TEMPERATURE (oC)
50
125
100
75
150
3092 G07
3092fb
TYPICAL PERFORMANCE CHARACTERISTICS
LT3092
Minimum Output Current
600
500
400
300
200
100
MINIMUM OUTPUT CURRENT (μA)
0
–50
–25 25
0
50
TEMPERATURE (°C)
Current Limit
400
350
300
250
200
150
CURRENT LIMIT (mA)
100
50
0
0
INPUT-TO-OUTPUT DIFFERENTIAL VOLTAGE (V)
Dropout Voltage Dropout Voltage
1.6
1.4
) (V)
OUT
– V
IN
DROPOUT VOLTAGE (V
125
100
75
150
3092 G08
1.2
1.0
0.8
0.6
0.4
0.2
0
0
TJ = –55°C
TJ = 25°C
TJ = 125°C
25
50
LOAD CURRENT (mA)
75 100 150125 175
200
3092 G09
1.4
1.2
) (V)
OUT
1.0
– V
IN
0.8
0.6
0.4
0.2
DROPOUT VOLTAGE (V
0
–50
–25 25
0
I
LOAD
I
LOAD
50
TEMPERATURE (°C)
75
= 200mA
= 100mA
100
125
150
3092 G10
Current Limit
500
450
400
350
300
250
200
150
CURRENT LIMIT (mA)
100
VIN = 7V
50
= 0V
V
TJ = 25°C
2
6810
4
3092 G11
OUT
0
–50
–25 25
0
TEMPERATURE (°C)
125
50
100
75
150
3092 G12
Line Transient Response Line Transient Response
8
6
4
2
INPUT VOLTAGE (V)
0
20
0
10
1mA CURRENT SOURCE
CONFIGURATION
40
30
50
TIME (µs)
1.5
1.0
OUTPUT CURRENT
0.5
DEVIATION (mA)
0
–0.5
–1.0
100
60
90
80
70
3092 G13
10
8
6
4
INPUT VOLTAGE (V)
2
0
20
10
10mA CURRENT SOURCE
CONFIGURATION
40
30
50
TIME (µs)
10
OUTPUT CURRENT
5
DEVIATION (mA)
0
–5
–10
100
60
90
80
70
3092 G14
3092fb
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LT3092
TYPICAL PERFORMANCE CHARACTERISTICS
8
6
4
2
INPUT VOLTAGE (V)
0
0
10
5
1mA CURRENT SOURCE
CONFIGURATION
20
15
25
TIME (µs)
Residual Output for Less Than
Minimum Output Current
800
SET PIN = 0V
700
600
500
400
300
OUTPUT VOLTAGE (mV)
200
100
0
0
V
IN
V
OUT
R
TEST
R
()
TEST
CURRENT (mA)
1.0
OUTPUT
0.5
0
50
35
VIN = 36V
VIN = 5V
45
40
3092 G15
20001000
3092 G17
30
8
6
4
2
INPUT VOLTAGE (V)
0
0
1G
100M
10M
1M
100k
10k
1k
OUTPUT IMPEDANCE ()
100
10
1
Turn-On ResponseTurn-On Response
10mA CURRENT SOURCE
CONFIGURATION
20
15
10
5
25
TIME (µs)
Output Impedance
I
= 1mA
SOURCE
I
=
SOURCE
10mA
I
= 100mA
SOURCE
100 1k 10k 100k 1M 10M10
FREQUENCY (Hz)
15
CURRENT (mA)
10
OUTPUT
5
0
50
30
45
40
35
3092 G16
3092 G18
6
Noise Spectral Density
100
10
1
REFERENCE CURRENT
0.1
NOISE SPECTRAL DENSITY (pA/√Hz)
0.01
FREQUENCY (Hz)
10k 100k10010 1k
3092 G19
3092fb
LT3092
PIN FUNCTIONS
(DD/ST/TS8)
IN (Pins 7, 8/Pin 3/Pins 7, 8): Input. This pin supplies
power to bias internal circuitry and supply output load
current. For the device to operate properly and regulate,
the voltage on this pin must be 1.2V to 1.4V above the
OUT pin (depending on output load current—see the
dropout voltage specifi cations in the Electrical Characteristics table).
NC (Pins 3, 5, 6/NA/Pins 1, 6): No Connection. These
pins have no connection to internal circuitry and may be
tied to IN, OUT, GND or fl oated.
OUT (Pins 1, 2/Pin 2/Pins 2, 3, 4): Output. This is the
power output of the device. The minimum current source
value to which the LT3092 can be set is 0.5mA or the
device will not regulate.
BLOCK DIAGRAM
SET (Pin 4/Pin 1/Pin 5): Set. This pin is the error amplifi er’s noninverting input and also sets the operating bias
point of the circuit. A fi xed 10A current source fl ows out
of this pin. Two resistors program I
as a function of
OUT
the resistor ratio relative to 10A. Output current range
is 0.5mA to the maximum rated 200mA level.
Exposed Pad/Tab (Pin 9/Tab/NA): Output. The Exposed
Pad of the DFN package and the Tab of the SOT-223
package are tied internally to OUT. Tie them directly to
the OUT pins (Pins 1, 2/Pin 2) at the PCB. The amount
of copper area and planes connected to OUT determine
the effective thermal resistance of the packages (see the
Applications Information section).
SET
IN
10µA
+
–
OUT
3092 BD
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