LM223.PDF

January 1995

LM123/LM323A/LM323

3-Amp, 5-Volt Positive Regulator

General Description

The LM123 is a three-terminal positive regulator with a pre-

set 5V output and a load driving capability of 3 amps. New

circuit design and processing techniques are used to pro-

vide the high output current without sacrificing the regulation

characteristics of lower current devices.

The LM323A offers improved precision over the standard

LM323. Parameters with tightened specifications include

output voltage tolerance, line regulation, and load regula-

tion.

The 3 amp regulator is virtually blowout proof. Current limit-

ing, power limiting, and thermal shutdown provide the same

high level of reliability obtained with these techniques in the

LM109 1 amp regulator.

No external components are required for operation of the

LM123. If the device is more than 4 inches from the filter

capacitor, however, a 1 m F solid tantalum capacitor should

be used on the input. A 0.1 m F or larger capacitor may be

used on the output to reduce load transient spikes created

by fast switching digital logic, or to swamp out stray load

capacitance.

An overall worst case specification for the combined effects

of input voltage, load currents, ambient temperature, and

power dissipation ensure that the LM123 will perform satis-

factorily as a system element.

For applications requiring other voltages, see LM150 series

adjustable regulator data sheet.

Operation is guaranteed over the junction temperature

range b 55 § Cto a 150 § C for LM123, b 40 § Cto a 125 § C for

LM323A, and 0 § Cto a 125 § C for LM323. A hermetic TO-3

package is used for high reliability and low thermal resist-

ance.

Features

Y Guaranteed 1% initial accuracy (A version)

Y 3 amp output current

Y Internal current and thermal limiting

Y 0.01 X typical output impedance

Y 7.5V minimum input voltage

Y 30W power dissipation

Y P a Product Enhancement tested

Connection Diagram

Metal Can Package

TL/H/7771±2

Order Number LM123K STEEL, LM323AK STEEL or LM323K STEEL

See NS Package Number K02A

Order Number LM123K/883

See NS Package Number K02C

Typical Applications

Basic 3 Amp Regulator

TL/H/7771±3

*Required if LM123 is more than 4 × from filter capacitor.

C 1995 National Semiconductor Corporation

TL/H/7771

RRD-B30M115/Printed in U. S. A.

Regulator is stable with no load capacitor into resistive loads.

Absolute Maximum Ratings

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales

Office/Distributors for availability and specifications.

(Note 4)

Input Voltage

Operating Junction Temperature Range

LM123

b 55 § Cto a 150 § C

LM323A

b 40 § Cto a 125 § C

LM323

0 § Cto a 125 § C

20V

Storage Temperature Range

b 65 § Cto a 150 § C

Power Dissipation

Internally Limited

Lead Temperature (Soldering, 10 sec.)

300 § C

ESD Tolerance (Note 5)

2000V

LM123 Electrical Characteristics (Note 1)

LM123

Parameter

Conditions

Units

Min

Typ

Max

Output Voltage

T j e 25 § C

4.7

5.3

V IN e 7.5V, I OUT e 0A

7.5V s V IN s 15V

0A s I OUT s 3A, P s 30W

4.6

5.4

Line Regulation (Note 3)

T j e 25 § C

7.5V s V IN s 15V

Load Regulation (Note 3)

T j e 25 § C, V IN e 7.5V,

100

0A s I OUT s 3A

Quiescent Current

7.5V s V IN s 15V,

0A s I OUT s 3A

Output Noise Voltage

T j e 25 § C

m Vrms

10 Hz s f s 100 kHz

Short Circuit Current Limit

T j e 25 § C

V IN e 15V

4.5

V IN e 7.5V

Long Term Stability

Thermal Resistance Junction

§ C/W

to Case (Note 2)

LM323A/LM323 Electrical Characteristics (Note 1)

LM323A

LM323

Parameter

Conditions

Units

Min Typ Max Min Typ Max

Output Voltage

T j e 25 § C

4.95

5.05 4.8

5.2

V IN e 7.5V, I OUT e 0A

7.5V s V IN s 15V

0A s I OUT s 3A, P s 30W

4.85

5.15 4.75

5.25

Line Regulation (Note 3)

T j e 25 § C

25 mV

7.5V s V IN s 15V

Load Regulation (Note 3)

T j e 25 § C, V IN e 7.5V,

100 mV

0A s I OUT s 3A

Quiescent Current

7.5V s V IN s 15V,

20 mA

0A s I OUT s 3A

Output Noise Voltage

T j e 25 § C

m Vrms

10 Hz s f s 100 kHz

Short Circuit Current Limit

T j e 25 § C

V IN e 15V

4.5

V IN e 7.5V

Long Term Stability

35 mV

Thermal Resistance Junction

§ C/W

to Case (Note 2)

Note 1: Unless otherwise noted, specifications apply for b 55 § C s T j s a 150 § C for the LM123, b 40 § C s T j s a 125 § C for the LM323A, and 0 § C s T j s a 125 § C

for the LM323. Although power dissipation is internally limited, specifications apply only for P s 30W.

Note 2: Without a heat sink, the thermal resistance of the TO-3 package is about 35 § C/W. With a heat sink, the effective thermal resistance can only approach the

specified values of 2 § C/W, depending on the efficiency of the heat sink.

Note 3: Load and line regulation are specified at constant junction temperature. Pulse testing is required with a pulse width s 1 ms and a duty cycle s 5%.

Note 4: Refer to RETS123K drawing for LM123K military specifications.

Note 5: Human body model, 1.5 k X in series with 100 pF.

Typical Applications (Continued)

Adjustable Output 5V±10V 0.1% Regulation

*Select to Set Output Voltage

TL/H/7771±4

**Select to Draw 25 mA from V b

Typical Performance Characteristics

Maximum Average Power

Dissipation for LM123

Dissipation for LM323A, LM323

Output Impedance

Peak Available Output Current Short Circuit Current

Ripple Rejection

Dropout Voltage

Line Transient Response

Output Voltage

Quiescent Current

Load Transient Response

Output Noise Voltage

TL/H/7771±5

Typical Applications (Continued)

10 Amp Regulator with Complete Overload Protection

*Select for 20 mA Current from Unregulated Negative Supply

TL/H/7771±6

Adjustable Regulator 0V±10V @ 3A

*R6 e

V b

12 mA

A 1 ÐLM101A

C 1 Ð2 m F OptionalÐImproves Ripple Rejection, Noise, and Transient Response

TL/H/7771±7

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