1
LT138A/LT338A
LM138/LM338
5A Positive Adjustable
Voltage Regulator
■
Guaranteed
1% Initial Tolerance
■
Guaranteed
0.3% Load Regulation
■
Guaranteed
5A Output Current
■
100% Thermal Limit Burn-In
■
12A Transient Output Current
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 excel-
lent 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.
The LT138A is an improved version of the popular LM138
with improved circuit design and advanced process tech-
niques to provide superior performance and reliability.
The graph below shows the significant improvement in
output voltage tolerance achieved by using the LT138A or
LT338A.
■
High Power Linear Regulator
■
Battery Chargers
■
Power Driver
■
Constant-Current Regulator
, LTC and LT are registered trademarks of Linear Technology Corporation.
Parallel Regulators for Higher Current*
LT338A 0.01Ω**
V
IN
V
IN
THIS CIRCUIT WILL NOT WORK WITH LM VERSION DEVICES
CURRENT SHARING RESISTORS DEGRADE REGULATION TO 1%
*
**
V
OUT
ADJ
LT350A
V
IN
138/338 TA01
121Ω
1%
5V
8A
V
OUT
ADJ
0.016Ω**
365Ω
1%
Output Voltage Error
OUTPUT VOLTAGE (V)
1
0
OUTPUT VOLTAGE ERROR (%)
3
5
7
10
10 100
138A/338A TA02
1
4
6
9
12
11
8
2
2% RESISTORS
2% RESISTORS
1% RESISTORS
1% RESISTORS
LM338
LM338
LT338A
LT338A
DESCRIPTIO
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FEATURES
APPLICATIO S
U
TYPICAL APPLICATIO
U
2
LT138A/LT338A
LM138/LM338
A
U
G
W
A
W
U
W
ARBSOLUTEXI T
IS
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
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
PRECONDITIONI G
UUU
100% Thermal Limit Burn-In
(Note 1)
LT138A LM138
SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS
V
REF
Reference Voltage I
OUT
= 10mA, T
J
= 25°C 1.238 1.250 1.262 V
3V ≤ (V
IN
– V
OUT
) ≤ 35V, ●1.225 1.250 1.270 1.19 1.24 1.29 V
10mA ≤ I
OUT
≤ 5A, P ≤ 50W
∆V
OUT
Line Regulation 3V ≤ (V
IN
– V
OUT
) ≤ 35V, (Note 3) 0.005 0.01 0.005 0.01 %/V
∆V
IN
●0.02 0.04 0.02 0.04 %/V
∆V
OUT
Load Regulation 10mA ≤ I
OUT
≤ 5A, (Note 3)
∆I
OUT
V
OUT
≤ 5V 5 15 5 15 mV
V
OUT
≥ 5V 0.1 0.3 0.1 0.3 %
V
OUT
≤ 5V ●20 30 20 30 mV
V
OUT
≥ 5V ●0.3 0.6 0.3 0.6 %
Thermal Regulation 20ms Pulse 0.002 0.01 0.002 0.01 %/W
Ripple Rejection V
OUT
= 10V, f = 120Hz
C
ADJ
= 0µF●60 60 dB
C
ADJ
= 10µF●60 75 60 75 dB
I
ADJ
Adjust Pin Current ●45 100 45 100 µA
∆I
ADJ
Adjust Pin Current Change 10mA ≤ I
OUT
≤ 5A, ●0.2 5 0.2 5 µA
3V ≤ (V
IN
– V
OUT
) ≤ 35V
Minimum Load Current (V
IN
– V
OUT
) = 35V ●3.5 5 3.5 5 mA
I
SC
Current Limit (V
IN
– V
OUT
) ≤ 10V
DC ●58 58 A
0.5ms Peak ●612 612 A
(V
IN
– V
OUT
) = 30V, T
J
= 25°C121A
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2)
WU
U
PACKAGE/ORDER I FOR ATIO
ORDER
PART NUMBER
LT138AK
LT338AK
LM138K
LM338K
T
JMAX
= 150°C, θ
JA
= 35°C/W, θ
JC
= 1°C/ W (LT138A/LT138)
T
JMAX
= 125°C, θ
JA
= 35°C/W, θ
JC
= 1°C/ W (LT338A/LT338)
Consult factory for Industrial grade parts.
ORDER
PART NUMBER
LM338P
V
OUT
V
IN
ADJ
3
2
1
FRONT VIEW
P PACKAGE
3-LEAD PLASTIC TO-3P
T
JMAX
= 125°C, θ
JA
= 45°C/W
2
1
V
IN
CASE
IS OUTPUT
ADJ
K PACKAGE
2-LEAD TO-3 METAL CAN
BOTTOM VIEW
3
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)
LT138A LM138
SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS
∆V
OUT
Temperature Stability ●12 1 %
∆Temp
∆V
OUT
Long-Term Stability T
A
= 125°C, 1000 Hours 0.3 1 0.3 1 %
∆Time
e
n
RMS Output Noise (% of V
OUT
) 10Hz ≤ f ≤ 10kHz 0.001 0.003 %
θ
JC
Thermal Resistance K Package 1 1 °C/W
Junction-to-Case
The ● denotes specifications which apply over the full operating temperature range,
otherwise specifications are at TA = 25°C. (Note 2)
LT338A LM338
SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS
V
REF
Reference Voltage I
OUT
= 10mA 1.238 1.250 1.262 V
3V ≤ (V
IN
– V
OUT
) ≤ 35V, ●1.225 1.250 1.270 1.19 1.24 1.29 V
10mA ≤ I
OUT
≤ 5A, P ≤ 50W
∆V
OUT
Line Regulation 3V ≤ (V
IN
– V
OUT
) ≤ 35V, (Note 3) 0.005 0.01 0.005 0.03 %/V
∆V
IN
●0.02 0.04 0.02 0.06 %/V
∆V
OUT
Load Regulation 10mA ≤ I
OUT
≤ 5A, (Note 3)
∆I
OUT
V
OUT
≤ 5V 5 15 5 25 mV
V
OUT
≥ 5V 0.1 0.3 0.1 0.5 %
V
OUT
≤ 5V ●20 30 20 50 mV
V
OUT
≥ 5V ●0.3 0.6 0.3 1 %
Thermal Regulation 20ms Pulse 0.002 0.02 0.002 0.02 %/W
Ripple Rejection V
OUT
= 10V, f = 120Hz
C
ADJ
= 0µF●60 60 dB
C
ADJ
= 10µF●60 75 60 75 dB
I
ADJ
Adjust Pin Current ●45 100 45 100 µA
∆I
ADJ
Adjust Pin Current Change 10mA ≤ I
OUT
≤ 5A, ●0.2 5 0.2 5 µA
3V ≤ (V
IN
– V
OUT
) ≤ 35V
Minimum Load Current (V
IN
– V
OUT
) = 35V ●3.5 10 3.5 10 mA
I
SC
Current Limit (V
IN
– V
OUT
) ≤ 10V
DC ●58 58 A
0.5ms Peak ●612 612 A
(V
IN
– V
OUT
) = 30V, T
J
= 25°C121A
∆V
OUT
Temperature Stability ●12 1 %
∆Temp
∆V
OUT
Long-Term Stability T
A
= 125°C, 1000 Hours 0.3 1 0.3 1 %
∆Time
e
n
RMS Output Noise (% of V
OUT
) 10Hz ≤ f ≤ 10kHz 0.001 0.003 %
θ
JC
Thermal Resistance K Package 1 1 °C/W
Junction-to-Case
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:
V
IN
– V
OUT
= 5V and I
OUT
= 2.5A. These specifications are applicable for
power dissipations up to 50W.
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.
4
LT138A/LT338A
LM138/LM338
TYPICAL PERFOR A CE CHARACTERISTICS
UW
TEMPERATURE (°C)
–75
–0.4
OUTPUT VOLTAGE DEVIATION (%)
–0.3
–0.1
0
0.1
–25 25 50 150
138/338 G01
–0.2
–50 0 75 100 125
0.2
I
OUT
= 5A
I
OUT
= 3A
V
IN
= 15V
V
OUT
= 10V
PRELOAD = 50mA
Load RegulationLoad Regulation
TEMPERATURE (°C)
–50
1.230
REFERENCE VOLTAGE (V)
1.240
1.250
1.260
1.270
–25 0 25 50
138A/338A G04
75 100 125 150
Temperature Stability
INPUT-OUTPUT DIFFERENTIAL (V)
0
QUIESCENT CURRENT (mA)
3
4
5
15 25 40
138A/338A G06
2
1
0510 20 30 35
T
J
= 25°C
T
J
= 150°C
T
J
= –55°C
TEMPERATURE (°C)
–75
ADJUSTMENT CURRENT (µA)
35
40
45
75
65
138A/338A G03
30 –25 25 125
50
55
60
Adjustment Current
TEMPERATURE (°C)
–75
1
INPUT-OUTPUT DIFFERENTIAL (V)
3
–25 25 50 150
138/338 G02
2
–50 0 75 100 125
4
I
OUT
= 5A
I
OUT
= 3A
I
OUT
= 1A
∆V
OUT
= 100mV
Dropout Voltage
FREQUENCY (Hz)
10
OUTPUT IMPEDANCE (Ω)
0.1
1
10
100k
138/338 G05
0.01
0.001
0.0001 100 1k 10k 1M
V
IN
= 15V
V
OUT
= 10V
I
OUT
= 500mA
C
ADJ
= C
OUT
= 10µF
C
ADJ
= C
OUT
= 0µF
Output Impedance Minimum Operating Current
Ripple Rejection Ripple RejectionRipple Rejection
OUTPUT VOLTAGE (V)
05
0
RIPPLE REJECTION (dB)
40
100
10 20 25
138A/338A G07
20
80
60
15 30 35
C
ADJ
= 10µF
C
ADJ
= 0µF
V
IN
– V
OUT
= 5V
I
OUT
= 500mA
f = 120Hz
T
J
= 25°C
FREQUENCY (Hz)
10
RIPPLE REJECTION (dB)
60
80
100
100k
138A/338A G08
40
20
0100 1k 10k 1M
C
ADJ
= 10µF
C
ADJ
= 0µF
V
IN
= 15V
V
OUT
= 10V
I
OUT
= 0.2A
OUTPUT CURRENT (A)
0.1
40
RIPPLE REJECTION (dB)
50
60
80
110
138/338 G09
70
CADJ = 10µF
CADJ = 0µF
VIN = 15V
VOUT = 10V
f = 120Hz
TCASE = 25°C
5
LT138A/LT338A
LM138/LM338
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Current Limit Current LimitCurrent Limit
INPUT-OUTPUT DIFFERENTIAL (V)
0
OUTPUT CURRENT (A)
8
12
40
138A/338A G10
4
010 20 30
16 PEAK CURRENT LIMIT
DC CURRENT LIMIT
T
CASE
= 25°C
PRELOAD = 0A
PRELOAD = 1A
PRELOAD = 5A
TIME (ms)
0.1
8
OUTPUT CURRENT (A)
10
12
14
1 10 100
138A/338A G11
6
4
2
0
PRELOAD = 0A
PRELOAD = 5A
V
IN
= 10V
V
OUT
= 5V
T
CASE
= 25°C
TIME (ms)
0.1
8
OUTPUT CURRENT (A)
10
12
14
1 10 100
138A/338A G12
6
4
2
0
PRELOAD CURRENT = 0
T
CASE
= 25°C
V
IN
– V
OUT
= 10V
V
IN
– V
OUT
= 15V
V
IN
– V
OUT
= 20V
V
IN
– V
OUT
= 30V
Line Transient Response
TIME (µs)
0
0
OUTPUT VOLTAGE
DEVIATION (V)
INPUT VOLTAGE
CHANGE (V)
0.5
–1.5
–1.0
–0.5
20 30
1.5
138A/338A G13
1.0
10 40
0
0.5
1.0
C
L
= 1µF
C
L
= 10µF
C
OUT
= 0
C
ADJ
= 0
V
OUT
= 10V
I
OUT
= 50mA
T
J
= 25°C
Load Transient Response
TIME (µs)
0
OUTPUT VOLTAGE
DEVIATION (V)LOAD CURRENT (A)
2
6
–3
–2
3
0
20 40
138A/338A G14
4
1
2
–1
010 30
VIN = 15V
VOUT = 10V
TCASE = 25°C
PRELOAD = 100mA
CL = 1µF
CADJ = 10µFCL = 0
CADJ = 0
APPLICATIONS INFORMATION
WUUU
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 con-
stant 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 I
ADJ
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 V
REF
. Earlier adjustable regulators had a reference
tolerance of ±4% which is dangerously close to the ±5%
supply tolerance required in many logic and analog sys-
tems. Further, even 1% resistors can drift 0.01%/°C, add-
ing additional error to the output voltage tolerance.
Figure 1. Basic Adjustable Regulator
LT338A
V
IN
R1
138A/338A F01
V
OUT
I
ADJ
50µA
ADJ V
REF
V
OUT
V
IN
R2
V
OUT
= V
REF
R2
R1
1 + + I
ADJ
• R2
()
+
6
LT138A/LT338A
LM138/LM338
For example, using 2% resistors and ±4% tolerance for
V
REF
, calculations will show that the expected range of a
5V regulator design would be 4.66V ≤ V
OUT
≤ 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 expen-
sive and not conductive to volume production.
One of the enhancements of Linear Technology’s adjust-
able regulators over existing devices is the tightened
initial tolerance of V
REF
. This allows relatively inexpen-
sive 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 1.47 2.15 3.16 4.64 6.81
1.02 1.50 2.21 3.24 4.75 6.98
1.05 1.54 2.26 3.32 4.87 7.15
1.07 1.58 2.32 3.40 4.99 7.32
1.10 1.62 2.37 3.48 5.11 7.50
1.13 1.65 2.43 3.57 5.23 7.68
1.15 1.69 2.49 3.65 5.36 7.87
1.18 1.74 2.55 3.74 5.49 8.06
1.21 1.78 2.61 3.83 5.62 8.25
1.24 1.82 2.67 3.92 5.76 8.45
1.27 1.87 2.74 4.02 5.90 8.66
1.30 1.91 2.80 4.12 6.04 8.87
1.33 1.96 2.87 4.22 6.19 9.09
1.37 2.00 2.94 4.32 6.34 9.31
1.40 2.05 3.01 4.42 6.49 9.53
1.43 2.10 3.09 4.53 6.65 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
APPLICATIONS INFORMATION
WUUU
(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 possi-
bility 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 capaci-
tor 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.
LT338A
D1
1N4002
V
IN
R1 NOT
NEEDED
138A/338A F02
V
OUT
ADJ
V
OUT
V
IN
R2
C
ADJ
10µFC
OUT
100µF
+
Figure 2
Load Regulation
Because the LT138A is a three-terminal device, it is not
possible to provide true remote load sensing. Load regu-
lation will be limited by the resistance of the wire connect-
ing 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 connec-
tion, with the bottom of the output divider returned to the
7
LT138A/LT338A
LM138/LM338
APPLICATIONS INFORMATION
WUUU
negative side of the load. Although it may not be immedi-
ately 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 be-
tween the regulator and the load would be:
RRR
RR ParasiticLine sis ce
PP
21
1
+
=, Re tan
Connected as shown, R
P
is not multiplied by the divider
ratio. R
P
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.
LT338A
R
P
PARASITIC
LINE RESISTANCE
V
IN
R1
CONNECT
R1 TO CASE
CONNECT
R2 TO LOAD
138A/338A F03
V
OUT
ADJ
V
IN
R
L
R2
Figure 3. Connections for Best Load Regulation
TYPICAL APPLICATIONS
U
Improving Ripple Rejection
LT338A
V
IN
R1
121Ω
1%
R2
365Ω
1%
1µF
*C1 IMPROVES RIPPLE REJECTION, X
C
SHOULD BE SMALL COMPARED TO R2
C
L
*
10µF
138A/338A TA03
V
OUT
ADJ
5VV
IN
+
+
1.2V to 25V Adjustable Regulator
LT338A
V
IN
R1
240Ω
C1*
1µF
NEEDED IF DEVICE IS FAR FROM FILTER CAPACITORS
OPTIONAL, IMPROVES TRANSIENT RESPONSE
R2
5k
138A/338A TA04
V
OUT
ADJ
V
OUT
†
V
IN
+
C2**
1µF
*
**
+
†
V
OUT
= 1.25V R2
R1
1 +
()
8
LT138A/LT338A
LM138/LM338
TYPICAL APPLICATIONS
U
5V Regulator with Shutdown
LT338A
V
IN
121Ω
1%
1µF
138A/338A TA05
V
OUT
ADJ
5V
2N3904
V
IN
TTL 365Ω
1%
1k
1k
+
LT338A
V
IN
V
IN
RETURN
V
OUT
ADJ
+
–
+
LM301A
V
IN
100pF
138A/338A TA06
1k
25Ω
R
P
(MAX DROP
300mV)
25Ω
121ΩR
L
365Ω
5µF
6
1
2
7
V
OUT
5V
RETURN
3
84
LT338A
V
IN
243Ω
1%
138A/338A TA07
V
OUT
2N3906
ADJ
3A
50k
2k
10k
12V
50Ω
Temperature Compensated Lead Acid Battery Charger
Remote Sensing
9
LT138A/LT338A
LM138/LM338
SCHE ATIC DIAGRA
WW
200Ω
300Ω
V
IN
V
OUT
ADJ
120Ω
3Ω
16k
Q27
Q26
Q22
Q25
12k
1.6k
6.7k
20k5.6k50Ω190Ω310Ω310Ω
C3
5pF
D1
18k
Q24
Q23
Q21
Q19
Q13
Q9
Q6Q4
Q1
Q18
Q16
Q28
160Ω
160k
0.01Ω
138A/338A SS
400Ω
2.4k
3k
12.4k
130Ω
4k
30k
12k
5.1k4.1k
10Ω4.1k180Ω
Q1
160k
D2
Q14
Q20
Q17
C2
30pF
C1
30pF
+
+
Q12
Q7
Q10
Q8
Q3
Q2 Q15
Q11
Q5
LT138A/LT338A
10
LT138A/LT338A
LM138/LM338
PACKAGE DESCRIPTION
U
Dimensions in inches (millimeters) unless otherwise noted.
K Package
2-Lead TO-3 Metal Can
(LTC DWG # 05-08-1310)
K2 (TO-3) 1098
0.038 – 0.043
(0.965 – 1.09)
0.060 – 0.135
(1.524 – 3.429)
0.320 – 0.350
(8.13 – 8.89)
0.420 – 0.480
(10.67 – 12.19)
0.760 – 0.775
(19.30 – 19.69)
0.490 – 0.510
(12.45 – 12.95)
R
0.167 – 0.177
(4.24 – 4.49)
R
0.151 – 0.161
(3.86 – 4.09)
DIA, 2PLCS
1.177 – 1.197
(29.90 – 30.40)
0.655 – 0.675
(16.64 – 17.15)
0.067 – 0.077
(1.70 – 1.96)
0.210 – 0.220
(5.33 – 5.59)
0.425 – 0.435
(10.80 – 11.05)
11
LT138A/LT338A
LM138/LM338
P Package
3-Lead Plastic TO-3P (Similar to TO-247)
(LTC DWG # 05-08-1450)
PACKAGE DESCRIPTION
U
Dimensions in inches (millimeters) unless otherwise noted.
0.580 – 0.6OO
(14.73 – 15.24)
0.170
(4.32)
MAX
0.325
(8.255)
0.580
(14.732)
0.560
(14.224) 0.620 – 0.64O
(15.75 – 16.26)
0.170 – 0.2OO
(4.32 – 5.08)
MOUNTING HOLE
0.115 – 0.145
(2.92 – 3.68)
DIA
0.580 – 0.6OO
(14.73 – 15.24)
0.830 – 0.870
(21.08 – 22.10)
0.780 – 0.800
(19.81 – 20.32)
0.620 – 0.64O
(15.75 – 16.26)
0.215
(5.46)
BSC
0.113 – 0.123
(2.87 – 3.12)
0.042 – 0.052
(1.07 – 1.32)
0.074 – 0.084
(1.88 – 2.13)
0.187 – 0.207
(4.75 – 5.26)
0.060 – 0.080
(1.52 – 2.03)
18° – 22°
3° – 7°
0.087 – 0.102
(2.21 – 2.59)
0.020 – 0.040
(0.51 – 1.02)
EJECTOR PIN MARKS
0.105 – 0.125
(2.67 – 3.18)
DIA
P3 0996
0.098
(2.489)
0.124
(3.149)
0.700
(17.780)
0.275
(6.985)
BOTTOM VIEW OF TO-3P
HATCHED AREA IS SOLDER PLATED
COPPER HEAT SINK
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 represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
12
LT138A/LT338A
LM138/LM338
RELATED PARTS
LINEAR TECHNOLOGY CORPORATIO N 1991
138afa LT/LT 1199 2K REV A • PRINTED IN THE USA
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear-tech.com
PART NUMBER DESCRIPTION COMMENTS
LT1084 5A Low Dropout Operates to 30V Input
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
LT1585/LT1587 7A/4.6A/3A Low Dropout Fast Transient Response Regulator For 1.2V to 3.3V Outputs from 5V
Lamp Flasher
LT338A
V
IN
138A/338A TA08
V
OUT
ADJ
12k
1µF10µF
12V
15V
12k
1k
OFF
12k
+
+
10µF
10µF
+
2N3904
+
Automatic Light Control
LT338A
V
IN
138A/338A TA09
V
OUT
ADJ 1.2k
Protected High Current Lamp Driver
LT338A
V
OUT
12V
5A
138A/338A TA10
V
IN
TTL OR
CMOS
ADJ
15V
10k
TYPICAL APPLICATIONS
U
