LINER LT338A

LT138A/LT338A
LM138/LM338
5A Positive Adjustable
Voltage Regulator
U
FEATURES
■
■
■
■
■
DESCRIPTIO
The LT®138A series of adjustable regulators provide 5A
output current over an output voltage range of 1.2V to 32V.
The internal voltage reference is trimmed to less than 1%,
enabling a very tight output voltage. In addition to excellent line and load regulation, with full overload protection,
the LT138A incorporates new current limiting circuitry
allowing large transient load currents to be handled for
short periods. Transient load currents of up to 12A can be
supplied without limiting, eliminating the need for a large
output capacitor.
Guaranteed 1% Initial Tolerance
Guaranteed 0.3% Load Regulation
Guaranteed 5A Output Current
100% Thermal Limit Burn-In
12A Transient Output Current
U
APPLICATIO S
■
■
■
■
High Power Linear Regulator
Battery Chargers
Power Driver
Constant-Current Regulator
The LT138A is an improved version of the popular LM138
with improved circuit design and advanced process techniques to provide superior performance and reliability.
The graph below shows the significant improvement in
output voltage tolerance achieved by using the LT138A or
LT338A.
, LTC and LT are registered trademarks of Linear Technology Corporation.
U
TYPICAL APPLICATIO
Parallel Regulators for Higher Current*
Output Voltage Error
12
VIN
VIN
0.01Ω**
VOUT
5V
8A
ADJ
LT350A
VIN
0.016Ω**
VOUT
ADJ
121Ω
1%
365Ω
1%
11
OUTPUT VOLTAGE ERROR (%)
LT338A
10
9
2% RESISTORS
8
7
1% RESISTORS
6
LM338
LM338
LT338A
5
4
2% RESISTORS
3
LT338A
1% RESISTORS
2
1
0
138/338 TA01
*THIS CIRCUIT WILL NOT WORK WITH LM VERSION DEVICES
**CURRENT SHARING RESISTORS DEGRADE REGULATION TO 1%
1
10
OUTPUT VOLTAGE (V)
100
138A/338A TA02
138afb
1
LT138A/LT338A
LM138/LM338
RATI GS
(Note 1)
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
U
W
Power Dissipation .............................. Internally Limited
Input-to-Output Voltage Differential ........................ 35V
Operating Junction Temperature Range
LT138A/LM138 ............................... – 55°C to 150°C
LT338A/LM338 ................................... 0°C to 125°C
UU
W W
AXI U
U
ABSOLUTE
PRECONDITIONI G
100% Thermal Limit Burn-In
U
W
U
PACKAGE/ORDER I FOR ATIO
BOTTOM VIEW
ORDER
PART NUMBER
ORDER
PART NUMBER
VIN
2
CASE
IS OUTPUT
1
ADJ
FRONT VIEW
LT138AK
LT338AK
LM138K
LM338K
K PACKAGE
2-LEAD TO-3 METAL CAN
LM338P
3
VOUT
2
VIN
1
ADJ
P PACKAGE
3-LEAD PLASTIC TO-3P
TJMAX = 150°C, θJA = 35°C/ W, θJC = 1°C/ W (LT138A/LT138)
TJMAX = 125°C, θJA = 35°C/ W, θJC = 1°C/ W (LT338A/LT338)
TJMAX = 125°C, θJA = 45°C/ W
OBSOLETE PACKAGE
Consider the P Package for Alternate Source
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2)
LT138A
TYP
MAX
SYMBOL
PARAMETER
CONDITIONS
MIN
VREF
Reference Voltage
IOUT = 10mA, TJ = 25°C
1.238
1.250
1.262
1.225
1.250
1.270
0.005
0.02
3V ≤ (VIN – VOUT) ≤ 35V,
10mA ≤ IOUT ≤ 5A, P ≤ 50W
∆VOUT
∆VIN
∆VOUT
∆IOUT
Line Regulation
●
3V ≤ (VIN – VOUT) ≤ 35V, (Note 3)
●
Load Regulation
10mA ≤ IOUT ≤ 5A, (Note 3)
VOUT ≤ 5V
VOUT ≥ 5V
VOUT ≤ 5V
VOUT ≥ 5V
Thermal Regulation
20ms Pulse
Ripple Rejection
VOUT = 10V, f = 120Hz
CADJ = 0µF
CADJ = 10µF
●
●
●
●
60
MIN
LM138
TYP
MAX
UNITS
V
1.24
1.29
V
0.01
0.04
0.005
0.02
0.01
0.04
%/V
%/V
5
0.1
15
0.3
5
0.1
15
0.3
mV
%
20
0.3
30
0.6
20
0.3
30
0.6
mV
%
0.002
0.01
0.002
0.01
%/W
60
75
1.19
60
60
75
dB
dB
IADJ
Adjust Pin Current
●
45
100
45
100
µA
∆IADJ
Adjust Pin Current Change
10mA ≤ IOUT ≤ 5A,
3V ≤ (VIN – VOUT) ≤ 35V
●
0.2
5
0.2
5
µA
Minimum Load Current
(VIN – VOUT) = 35V
●
3.5
5
3.5
5
mA
138afb
2
LT138A/LT338A
LM138/LM338
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
ISC
Current Limit
(VIN – VOUT) ≤ 10V
DC
0.5ms Peak
MIN
●
●
5
6
(VIN – VOUT) = 30V, TJ = 25°C
∆VOUT
∆Temp
∆VOUT
∆Time
Temperature Stability
en
RMS Output Noise (% of VOUT) 10Hz ≤ f ≤ 10kHz
θJC
Thermal Resistance
Junction-to-Case
Long-Term Stability
●
TA = 125°C, 1000 Hours
LT138A
TYP
MAX
8
12
MIN
LM138
TYP
5
6
8
12
MAX
UNITS
A
A
1
2
1
A
1
2
1
%
0.3
1
0.3
0.001
K Package
1
0.003
1
%
%
1
°C/W
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 2)
SYMBOL
PARAMETER
VREF
Reference Voltage
CONDITIONS
MIN
IOUT = 10mA
3V ≤ (VIN – VOUT) ≤ 35V,
10mA ≤ IOUT ≤ 5A, P ≤ 50W
∆VOUT
∆VIN
∆VOUT
∆IOUT
Line Regulation
20ms Pulse
Ripple Rejection
VOUT = 10V, f = 120Hz
CADJ = 0µF
CADJ = 10µF
UNITS
1.19
1.24
1.29
V
1.250
1.262
1.270
0.005
0.02
0.01
0.04
0.005
0.02
0.03
0.06
%/V
%/V
5
0.1
15
0.3
5
0.1
25
0.5
mV
%
20
0.3
30
0.6
20
0.3
50
1
mV
%
0.002
0.02
0.002
0.02
%/W
●
●
●
●
MAX
1.250
10mA ≤ IOUT ≤ 5A, (Note 3)
VOUT ≤ 5V
VOUT ≥ 5V
Thermal Regulation
LM338
TYP
1.238
●
Load Regulation
MIN
1.225
3V ≤ (VIN – VOUT) ≤ 35V, (Note 3)
VOUT ≤ 5V
VOUT ≥ 5V
60
60
75
V
60
60
75
dB
dB
●
45
100
45
100
µA
10mA ≤ IOUT ≤ 5A,
3V ≤ (VIN – VOUT) ≤ 35V
●
0.2
5
0.2
5
µA
Minimum Load Current
(VIN – VOUT) = 35V
●
3.5
10
3.5
10
mA
Current Limit
(VIN – VOUT) ≤ 10V
DC
0.5ms Peak
●
●
IADJ
Adjust Pin Current
∆IADJ
Adjust Pin Current Change
ISC
●
LT338A
TYP
MAX
(VIN – VOUT) = 30V, TJ = 25°C
∆VOUT
∆Temp
∆VOUT
∆Time
Temperature Stability
Long-Term Stability
TA = 125°C, 1000 Hours
en
RMS Output Noise (% of VOUT)
10Hz ≤ f ≤ 10kHz
θJC
Thermal Resistance
Junction-to-Case
K Package
●
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: Unless otherwise specified, these specifications apply:
VIN – VOUT = 5V and IOUT = 2.5A. These specifications are applicable for
power dissipations up to 50W.
5
6
8
12
5
6
8
12
A
A
1
2
1
A
1
2
1
%
0.3
1
0.3
0.001
1
0.003
1
%
%
1
°C/W
Note 3: 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.
138afb
3
LT138A/LT338A
LM138/LM338
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Load Regulation
4
0
IOUT = 3A
– 0.1
IOUT = 5A
– 0.2
– 0.3
– 0.4
–75 – 50 – 25
∆VOUT = 100mV
60
3
IOUT = 5A
IOUT = 3A
2
IOUT = 1A
1
–75 – 50 – 25
0 25 50 75 100 125 150
TEMPERATURE (°C)
Temperature Stability
40
1.260
1.250
1.240
VIN = 15V
VOUT = 10V
IOUT = 500mA
1
CADJ = COUT = 0µF
0.1
0.01
CADJ = COUT = 10µF
0.0001
4
TJ = 150°C
TJ = 25°C
3
TJ = – 55°C
2
1
0
10
100
10k
1k
FREQUENCY (Hz)
100k
1M
25 30 35
5
10 15 20
INPUT-OUTPUT DIFFERENTIAL (V)
0
138/338 G05
Ripple Rejection
Ripple Rejection
80
100
CADJ = 10µF
CADJ = 10µF
80
CADJ = 0µF
60
40
VIN – VOUT = 5V
IOUT = 500mA
f = 120Hz
TJ = 25°C
20
15
10
25
OUTPUT VOLTAGE (V)
60
CADJ = 0µF
40
20
0
30
35
138A/338A G07
CADJ = 10µF
RIPPLE REJECTION (dB)
RIPPLE REJECTION (dB)
RIPPLE REJECTION (dB)
80
5
40
138A/338A G06
Ripple Rejection
100
0
125
Minimum Operating Current
138A/338A G04
20
25
75
TEMPERATURE (°C)
5
0.001
25 50 75 100 125 150
TEMPERATURE (°C)
–25
138A/338A G03
Output Impedance
10
OUTPUT IMPEDANCE (Ω)
REFERENCE VOLTAGE (V)
45
138/338 G02
1.270
0
50
30
–75
0 25 50 75 100 125 150
TEMPERATURE (°C)
138/338 G01
1.230
–50 –25
55
35
QUIESCENT CURRENT (mA)
0.1
Adjustment Current
65
ADJUSTMENT CURRENT (µA)
VIN = 15V
VOUT = 10V
PRELOAD = 50mA
INPUT-OUTPUT DIFFERENTIAL (V)
OUTPUT VOLTAGE DEVIATION (%)
0.2
Dropout Voltage
0
VIN = 15V
VOUT = 10V
IOUT = 0.2A
10
100
70
CADJ = 0µF
60
50
40
10k
1k
FREQUENCY (Hz)
100k
1M
138A/338A G08
VIN = 15V
VOUT = 10V
f = 120Hz
TCASE = 25°C
0.1
1
OUTPUT CURRENT (A)
10
138/338 G09
138afb
4
LT138A/LT338A
LM138/LM338
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Current Limit
Current Limit
PEAK CURRENT LIMIT
DC CURRENT LIMIT
TCASE = 25°C
14
14
12
12
8
PRELOAD = 1A
4
10
PRELOAD = 5A
8
6
4
2
0
20
10
30
INPUT-OUTPUT DIFFERENTIAL (V)
40
OUTPUT CURRENT (A)
PRELOAD = 5A
0
0
0.1
1
10
VIN – VOUT = 30V
1
10
100
TIME (ms)
138A/338A G12
138A/338A G11
Load Transient Response
OUTPUT VOLTAGE
DEVIATION (V)
3
CL = 1µF
CL = 10µF
– 0.5
COUT = 0
CADJ = 0
–1.0
1.0
0.5
0
10
20
TIME (µs)
40
30
2
1
CL = 1µF
CADJ = 10µF
CL = 0
CADJ = 0
0
–1
VIN = 15V
VOUT = 10V
TCASE = 25°C
PRELOAD = 100mA
–2
–3
–1.5
INPUT VOLTAGE
CHANGE (V)
VIN – VOUT = 20V
4
TIME (ms)
0
0
VIN – VOUT = 15V
6
0
0.1
100
LOAD CURRENT (A)
OUTPUT VOLTAGE
DEVIATION (V)
0.5
VOUT = 10V
IOUT = 50mA
TJ = 25°C
VIN – VOUT = 10V
8
2
Line Transient Response
1.0
10
VIN = 10V
VOUT = 5V
TCASE = 25°C
138A/338A G10
1.5
PRELOAD CURRENT = 0
TCASE = 25°C
PRELOAD = 0A
PRELOAD = 0A
12
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
16
Current Limit
6
4
2
0
0
10
20
TIME (µs)
138A/338A G13
30
40
138A/338A G14
U
W
U
U
APPLICATIONS INFORMATION
General
The LT138A develops a 1.25V reference voltage between
the output and the adjustable terminal (see Figure 1). By
placing a resistor, R1, between these two terminals, a constant current is caused to flow through R1 and down through
R2 to set the overall output voltage. Normally this current
is the specified minimum load current of 5mA or 10mA.
Because IADJ is very small and constant when compared
with the current through R1, it represents a small error and
can usually be ignored. It is easily seen from the output
voltage equation, that even if the resistors were of exact
value, the accuracy of the output is limited by the accuracy
of VREF. Earlier adjustable regulators had a reference
tolerance of ±4% which is dangerously close to the ±5%
supply tolerance required in many logic and analog systems. Further, even 1% resistors can drift 0.01%/°C, adding additional error to the output voltage tolerance.
LT338A
VIN
VIN
VOUT
ADJ
+
VOUT
VREF
R1
IADJ
50µA
R2
( )
138A/338A F01
VOUT = VREF 1 + R2 + IADJ • R2
R1
Figure 1. Basic Adjustable Regulator
138afb
5
LT138A/LT338A
LM138/LM338
U
U
W
U
APPLICATIONS INFORMATION
For example, using 2% resistors and ±4% tolerance for
VREF, calculations will show that the expected range of a
5V regulator design would be 4.66V ≤ VOUT ≤ 5.36V or
approximately ±7%. If the same example were used for a
15V regulator, the expected tolerance would be ±8%. With
these results most applications required some method of
trimming, usually a trim pot. This solution is both expensive and not conductive to volume production.
One of the enhancements of Linear Technology’s adjustable regulators over existing devices is the tightened
initial tolerance of VREF. This allows relatively inexpensive 1% or 2% film resistors to be used for R1 and R2 to
set the output voltage within an acceptable tolerance.
With a guaranteed 1% reference, a 5V power supply
design, using ±2% resistors, would have a worst-case
manufacturing tolerance of ±4%. If 1% resistors are used,
the tolerance will drop to ±2.5%. A plot of the worst-case
output voltage tolerance as a function of resistor tolerance
is shown on the front page of this data sheet.
For convenience, a table of standard 1% resistor values is
shown in Table 1.
Table 1. 0.5% and 1% Standard Resistance Values
1.00
1.02
1.05
1.07
1.10
1.13
1.15
1.18
1.21
1.24
1.27
1.30
1.33
1.37
1.40
1.43
1.47
1.50
1.54
1.58
1.62
1.65
1.69
1.74
1.78
1.82
1.87
1.91
1.96
2.00
2.05
2.10
2.15
2.21
2.26
2.32
2.37
2.43
2.49
2.55
2.61
2.67
2.74
2.80
2.87
2.94
3.01
3.09
3.16
3.24
3.32
3.40
3.48
3.57
3.65
3.74
3.83
3.92
4.02
4.12
4.22
4.32
4.42
4.53
4.64
4.75
4.87
4.99
5.11
5.23
5.36
5.49
5.62
5.76
5.90
6.04
6.19
6.34
6.49
6.65
6.81
6.98
7.15
7.32
7.50
7.68
7.87
8.06
8.25
8.45
8.66
8.87
9.09
9.31
9.53
9.76
Standard resistance values are obtained from the Decade Table by
multiplying by multiples of 10. As an example, 1.21 can represent 1.21Ω,
12.1Ω, 121Ω, 1.21k etc.
Bypass Capacitors
Input bypassing using a 1µF tantalum or 25µf electrolytic
is recommended when the input filter capacitors are more
than 5 inches from the device. Improved ripple rejection
(80dB) can be accomplished by adding a 10µF capacitor
from the ADJ pin to ground. Increasing the size of the
capacitor to 20µF will help ripple rejection at low output
voltage since the reactance of this capacitor should be
small compared to the voltage setting resistor, R2. For
improved AC transient response and to prevent the possibility of oscillation due to unknown reactive load, a 1µF
capacitor is also recommended at the output. Because of
their low impedance at high frequencies, the best type of
capacitor to use is solid tantalum.
Protection Diodes
The LT138A/LT338A do not require a protection diode
from the adjustment terminal to the output (see Figure 2).
Improved internal circuitry eliminates the need for this
diode when the adjustment pin is bypassed with a capacitor to improve ripple rejection.
If a very large output capacitor is used, such as a 100µF
shown in Figure 2, the regulator could be damaged or
destroyed if the input is accidentally shorted to ground or
crowbarred, due to the output capacitor discharging into
the output terminal of the regulator. To prevent this, a
diode D1 as shown, is recommended to safely discharge
the capacitor.
D1
1N4002
LT338A
VIN
VOUT
VIN
ADJ
VOUT
R1
CADJ
10µF
NOT
NEEDED
+
R2
COUT
100µF
138A/338A F02
Figure 2
Load Regulation
Because the LT138A is a three-terminal device, it is not
possible to provide true remote load sensing. Load regulation will be limited by the resistance of the wire connecting the regulator to the load. The data sheet specification
for load regulation is measured at the bottom of the
package. Negative side sensing is a true Kelvin connection, with the bottom of the output divider returned to the
138afb
6
LT138A/LT338A
LM138/LM338
U
W
U
U
APPLICATIONS INFORMATION
negative side of the load. Although it may not be immediately obvious, best load regulation is obtained when the
top of the resistor divider, R1, is connected directly to the
case not to the load. This is illustrated in Figure 3. If R1
were connected to the load, the effective resistance between the regulator and the load would be:
LT338A
VOUT
VIN
VIN
RP
PARASITIC
LINE RESISTANCE
ADJ
CONNECT
R1 TO CASE
R1
RL
R2
 R2 + R1
RP 
 , RP = Parasitic Line Re sistance
 R1 
CONNECT
R2 TO LOAD
138A/338A F03
Connected as shown, RP is not multiplied by the divider
ratio. RP is about 0.004Ω per foot using 16 gauge wire.
This translates to 4mV/ft at 1A load current, so it is
important to keep the positive lead between regulator and
load as short as possible, and use large wire or PC board
traces.
Figure 3. Connections for Best Load Regulation
U
TYPICAL APPLICATIONS
Improving Ripple Rejection
LT338A
VIN
VIN
+
VOUT
1µF
5V
R1
121Ω
1%
ADJ
R2
365Ω
1%
+
CL*
10µF
138A/338A TA03
*C1 IMPROVES RIPPLE REJECTION, XC
SHOULD BE SMALL COMPARED TO R2
1.2V to 25V Adjustable Regulator
LT338A
R1
240Ω
ADJ
+
VOUT†
VOUT
VIN
VIN
C1*
1µF
R2
5k
+
C2**
1µF
138A/338A TA04
*NEEDED IF DEVICE IS FAR FROM FILTER CAPACITORS
**OPTIONAL, IMPROVES TRANSIENT RESPONSE
( )
VOUT = 1.25V 1 + R2
R1
†
138afb
7
LT138A/LT338A
LM138/LM338
U
TYPICAL APPLICATIONS
5V Regulator with Shutdown
LT338A
VIN
VIN
VOUT
+
5V
121Ω
1%
ADJ
1µF
1k
TTL
2N3904
365Ω
1%
1k
138A/338A TA05
Temperature Compensated Lead Acid Battery Charger
LT338A
3A
VIN
VOUT
243Ω
1%
ADJ
10k
50Ω
12V
2N3906
2k
50k
138A/338A TA07
Remote Sensing
RP
(MAX DROP
300mV)
LT338A
VIN
VOUT
5V
VOUT
VIN
ADJ
VIN
–
2
+
3
7
121Ω
6
LM301A
1
8
365Ω
100pF
4
RL
1k
5µF
+
25Ω
25Ω
RETURN
RETURN
138A/338A TA06
138afb
8
160k
Q1
Q3
30k
180Ω
Q5
Q4
Q7
130Ω
4k
Q6
310Ω
Q8
4.1k
Q11
12.4k
Q9
190Ω
4.1k
Q10
10Ω
Q12 Q13
Q1
50Ω
Q14
5.1k
Q16
3k
Q15
+
5.6k
C2
30pF
+
C1
30pF
20k
Q17
Q18
ADJ
12k
Q19
2.4k
Q20
1.6k
Q21
Q22
6.7k
Q23
16k
Q25
C3
5pF
Q24
400Ω
12k
120Ω
Q26 200Ω
300Ω
160k
Q27
VOUT
160Ω
D2
18k
D1
138A/338A SS
0.01Ω
3Ω
Q28
SCHE ATIC DIAGRA
Q2
310Ω
VIN
LT138A/LT338A
LM138/LM338
W
W
LT138A/LT338A
138afb
9
LT138A/LT338A
LM138/LM338
U
PACKAGE DESCRIPTION
K Package
2-Lead TO-3 Metal Can
(Reference LTC DWG # 05-08-1310)
0.760 – 0.775
(19.30 – 19.69)
0.320 – 0.350
(8.13 – 8.89)
0.060 – 0.135
(1.524 – 3.429)
0.420 – 0.480
(10.67 – 12.19)
0.038 – 0.043
(0.965 – 1.09)
1.177 – 1.197
(29.90 – 30.40)
0.655 – 0.675
(16.64 – 17.15)
0.210 – 0.220
(5.33 – 5.59)
0.151 – 0.161
(3.86 – 4.09)
DIA, 2PLCS
0.167 – 0.177
(4.24 – 4.49)
R
0.425 – 0.435
(10.80 – 11.05)
0.067 – 0.077
(1.70 – 1.96)
0.490 – 0.510
(12.45 – 12.95)
R
K2 (TO-3) 1098
OBSOLETE PACKAGE
138afb
10
LT138A/LT338A
LM138/LM338
U
PACKAGE DESCRIPTION
P Package
3-Lead Plastic TO-3P (Similar to TO-247)
(Reference LTC DWG # 05-08-1450)
0.560
(14.224)
0.325
(8.255)
0.580
(14.732)
0.700
(17.780)
0.830 – 0.870
(21.08 – 22.10)
0.580 – 0.6OO
(14.73 – 15.24)
0.098
(2.489)
0.124
(3.149)
0.187 – 0.207
(4.75 – 5.26)
0.620 – 0.64O
(15.75 – 16.26)
0.275
(6.985)
MOUNTING HOLE
18° – 22°
0.115 – 0.145
(2.92 – 3.68)
DIA
0.060 – 0.080
(1.52 – 2.03)
0.170 – 0.2OO
(4.32 – 5.08)
EJECTOR PIN MARKS
0.105 – 0.125
(2.67 – 3.18)
DIA
3° – 7°
0.170
(4.32)
MAX
0.780 – 0.800
(19.81 – 20.32)
BOTTOM VIEW OF TO-3P
HATCHED AREA IS SOLDER PLATED
COPPER HEAT SINK
0.042 – 0.052
(1.07 – 1.32)
0.074 – 0.084
(1.88 – 2.13)
0.215
(5.46)
BSC
0.113 – 0.123
(2.87 – 3.12)
0.087 – 0.102
(2.21 – 2.59)
0.020 – 0.040
(0.51 – 1.02)
P3 0996
138afb
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.
11
LT138A/LT338A
LM138/LM338
U
TYPICAL APPLICATIONS
Lamp Flasher
Automatic Light Control
LT338A
15V
VIN
+
ADJ
1µF
LT338A
VOUT
VIN
+
12k
10µF
12k
10µF
1.2k
12V
+
OFF
VOUT
ADJ
10µF
+
1k
2N3904
138A/338A TA09
12k
138A/338A TA08
Protected High Current Lamp Driver
15V
12V
5A
LT338A
VIN
VOUT
ADJ
TTL OR
CMOS
10k
138A/338A TA10
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1083/LT1084/LT1085
3A/5A/7.5A Low Dropout Regulators
Fixed Outputs, VIN Up to 30V
LT1580
7A Fast Transient Response Regulator with 0.7V Dropout
For 3.3V to 2.xxV Applications
LT1581
10A Fast Transient Response Regulator
For 3.3V to 2.xxV Applications
LT1584/LT1585/LT1587
7A/4.6A/3A Low Dropout Fast Transient Response Regulator
For 1.2V to 3.3V Outputs from 5V
LT1764
3A Fast Transient Response Regulator
Dropout Voltage 340mV, Low Noise: 40µVRMS
138afb
12
Linear Technology Corporation
LT/CPI 1101 1.5K REV B • PRINTED IN THE USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
 LINEAR TECHNOLOGY CORPORATION 1991