LT138A/LT338A
LM138/LM338
5A Positive Adjustable
Voltage Regulator
FEATURES
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DESCRIPTION
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 limit-
ing 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.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Guaranteed 1% Initial Tolerance
Guaranteed 0.3% Load Regulation
Guaranteed 5A Output Current
100% Thermal Limit Burn-In
12A Transient Output Current
APPLICATIONS
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High Power Linear Regulator
Battery Chargers
Power Driver
Constant-Current Regulator
TYPICAL APPLICATION
Parallel Regulators for Higher Current*
12
LT338A
V
IN
V
IN
ADJ
V
OUT
0.01Ω∗∗
5V
8A
11
OUTPUT VOLTAGE ERROR (%)
10
9
8
7
6
5
4
3
2
1
0
138/338 TA01
Output Voltage Error
2% RESISTORS
1% RESISTORS
LM338
LM338
LT338A
LT350A
V
IN
ADJ
V
OUT
0.016Ω**
121Ω
1%
365Ω
1%
2% RESISTORS
LT338A
1% RESISTORS
1
10
OUTPUT VOLTAGE (V)
100
138A/338A TA02
*THIS CIRCUIT WILL NOT WORK WITH LM VERSION DEVICES
**CURRENT SHARING RESISTORS DEGRADE REGULATION TO 1%
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LINER [ LINEAR TECHNOLOGY ]
