LM150/LM350A/LM350
3-Amp Adjustable Regulators
General Description
The LM150 series of adjustable 3-terminal positive voltage
regulators is capable of supplying in excess of 3A over a
1.2V to 33V output range. They are exceptionally easy to
use and require only 2 external resistors to set the output
voltage. Further, both line and load regulation are compa-
rable to discrete designs. Also, the LM150 is packaged in
standard transistor packages which are easily mounted and
handled.
In addition to higher performance than fixed regulators, the
LM150 series offers full overload protection available only in
IC’s. Included on the chip are current limit, thermal overload
protection and safe area protection. All overload protection
circuitry remains fully functional even if the adjustment termi-
nal is accidentally disconnected.
Normally, no capacitors are needed unless the device is situ-
ated more than 6 inches from the input filter capacitors in
which case an input bypass is needed. An output capacitor
can be added to improve transient response, while bypass-
ing the adjustment pin will increase the regulator’s ripple re-
jection.
Besides replacing fixed regulators or discrete designs, the
LM150 is useful in a wide variety of other applications. Since
the regulator is “floating” and sees only the input-to-output
differential voltage, supplies of several hundred volts can be
regulated as long as the maximum input to output differential
is not exceeded, i.e., avoid short-circuiting the output.
By connecting a fixed resistor between the adjustment pin
and output, the LM150 can be used as a precision current
regulator.
achieved by clamping the adjustment terminal to ground
which programs the output to 1.2V where most loads draw
little current.
The part numbers in the LM150 series which have a K suffix
are packaged in a standard Steel TO-3 package, while those
with a T suffix are packaged in a TO-220 plastic package.
The LM150 is rated for 55C
≤
T
≤
+150C, while the
LM350A is rated for 40C
≤
T
J
≤
+125C, and the LM350 is
rated for 0C
≤
T
J
≤
+125C.
Supplies
with
electronic
shutdown
can
be
Features
n
Adjustable output down to 1.2V
n
Guaranteed 3A output current
n
Guaranteed thermal regulation
n
Output is short circuit protected
n
Current limit constant with temperature
n
P
+
Product Enhancement tested
n
86 dB ripple rejection
n
Guaranteed 1% output voltage tolerance (LM350A)
n
Guaranteed max. 0.01%/V line regulation (LM350A)
n
Guaranteed max. 0.3% load regulation (LM350A)
Applications
n
Adjustable power supplies
n
Constant current regulators
n
Battery chargers
Connection Diagrams
(TO-3 STEEL)
Metal Can Package
DS009061-4
Case is Output
Bottom View
Order Number LM150K STEEL
or LM350K STEEL
See NS Package Number K02A
Order Number LM150K/883
See NS Package Number K02C
(TO-220)
Plastic Package
DS009061-5
Front View
Order Number LM350AT or LM350T
See NS Package Number T03B
May 1998
L
1999 National Semiconductor Corporation
DS009061
www.national.com