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. Supplies with electronic shutdown can be

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 −55˚C

≤ T

LM350A is rated for −40˚C

≤ T

rated for 0˚C

≤ T

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

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

© 1999 National Semiconductor Corporation

DS009061

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