Datasheet LM345K-5.0 Datasheet (NSC)

TL/H/7785

LM145/LM345 Negative Three Amp Regulator

January 1995

LM145/LM345 Negative Three Amp Regulator

General Description

The LM145 is a three-terminal negative regulator with a
fixed output voltage of

b

5V and up to 3A load current capa­bility. This device needs only one external componentÐa
compensation capacitor at the output, making it easy to ap­ply. Worst case guarantees on output voltage deviation due
to any combination of line, load or temperature variation
assure satisfactory system operation.

Exceptional effort has been made to make the LM145 im­mune to overload conditions. The regulator has current lim­iting which is independent of temperature, combined with
thermal overload protection. Internal current limiting pro­tects against momentary faults while thermal shutdown pre­vents junction temperatures from exceeding safe limits dur­ing prolonged overloads.

Although primarily intended for fixed output voltage applica­tions, the LM145 may be programmed for higher output volt­ages with a simple resistive divider. The low quiescent drain

current of the device allows this technique to be used with
good regulation.

The LM145 comes in a hermetic TO-3 package rated at
25W. A reduced temperature range part LM345 is also avail­able.

Features

Y

Output voltage accurate to better thang2%

Y

Current limit constant with temperature

Y

Internal thermal shutdown protection

Y

Operates with input-output voltage differential of 2.8V at
full rated load over full temperature range

Y

Regulation guaranteed with 25W power dissipation

Y

3A output current guaranteed

Y

Only one external component needed

Y

PaProduct Enhancement tested

Schematic Diagram

TL/H/7785– 1

C

1995 National Semiconductor Corporation RRD-B30M115/Printed in U. S. A.

Absolute Maximum Ratings

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
(Note 3)

Input Voltage 20V

Input-Output Differential 20V

Power Dissipation Internally Limited

Operating Junction Temperature Range

LM145

b

55§Ctoa150§C

LM345 0

§

Ctoa125§C

Storage Temperature Range

b

65§Ctoa150§C

Lead Temperature (Soldering, 10 sec.) 300

§

C

Electrical Characteristics (Note 1)

Limits

Parameter Conditions LM145 LM345 Units

Min Typ Max Min Typ Max

Output Voltage T

j

e

25§C, I

OUT

e

5 mA,

b

5.1

b

5.0

b

4.9

b

5.2

b

5.0

b

4.8 V

V

IN

eb

7.5

Line Regulation (Note 2) T

j

e

25§C

5 15 5 25 mV

b

20VsV

IN

s

b

7.5V

Load Regulation (Note 2) T

j

e

25§C, V

IN

eb

7.5V
30 75 30 100 mV

5mAsI

OUT

s

3A

Output Voltage

b

20VsV

IN

s

b

7.8V

5mA

s

I

OUT

s

3A

P

s

25W

b

5.20

b

4.80b5.25

b

4.75 V

T

MIN

s

T

j

s

T

MAX

Quiescent Current

b

20VsV

IN

s

b

7.5V

1.0 3.0 1.0 3.0 mA

5mA

s

I

OUT

s

3A

Short Circuit Current V

IN

eb

7.5V, T

j

ea

25§C 4 5.5 4 5.5 A

V

IN

eb

20V, T

j

ea

25§C 2 3.5 2 3.5 A

Output Noise Voltage T

A

e

25§C, C

L

e

4.7 mF
150 150 mV

10 Hz

sfs

100 kHz

Long Term Stability 5 50 5 50 mV

Thermal Resistance

22

§

C/W

Junction to Case

Note 1: Unless otherwise specified, these specifications apply:b55§CsT

j

s

a

150§C for the LM145 and 0§CsT

j

s

a

125§C for the LM345. V

IN

e

7.5V and

I

OUT

e

5 mA. Although power dissipation is internally limited, electrical specifications apply only for power levels up to 25W. For calculations of junction

temperature rise due to power dissipation, use a thermal resistance of 35

§

C/W for the TO-3 with no heat sink. With a heat sink, use 2§C/W for junction to case

thermal resistance.

Note 2: Regulation is measured at constant junction temperature. Changes in output voltage due to heating effects must be taken into account separately. To
ensure constant junction temperature, pulse testing with a low duty cycle is used.

Note 3: Refer to RETS145K-5V for LM145K-5.0 military specifications.

Connection Diagram

Metal Can Package

TL/H/7785– 2

Bottom View

Order Number LM345K-5.0

See NS Package Number K02A

Order Number LM145K-5.0/883 or

SMD

Ý

5962-9064501

See NS Package Number K02C

Typical Applications

Fixed Regulator

TL/H/7785– 3

²

Required for stability. For value given, capacitor must be solid tantalum.
50 mF aluminum electrolytic may be substituted. Values given may be in­creased without limit.

*Required if regulator is separated from filter capacitor. For value given, ca-

pacitor must be solid tantulum. 50 mF aluminum electrolytic may be substi­tuted.

2

Typical Performance Characteristics

Dissipation for LM145

Maximum Average Power

Dissipation for LM345

Maximum Average Power

Ripple Rejection

Output Impedance Voltage Differential

Minimum Input-Output

Temperature

Output Voltage vs

TL/H/7785– 4

Typical Applications (Continued)

TL/H/7785– 5

*Select resistors to set output voltage. 1 ppm/C tracking suggested.

**C1 is not needed if power supply filter capacitor is within 3

×

of regulator.

²

Determines zener current. May be adjusted to minimize temperature drift.

²²

Solid tantalum.

Load and line regulation

k

0.01%

Temperature drift

k

0.001%/C

3

Typical Applications (Continued)

High Stability Regulator

TL/H/7785– 6

**C1 is not needed if power supply filter capacitor is within 3×of regulator.

²

Keep C4 within 2×of LM345.

**D2 sets initial output voltage accuracy. The LM113 is available in

b5,b

2, andb1% tolerance.

b

2V ECL Termination Regulator

Dual 3 Amp Trimmed Supply

TL/H/7785– 7

Variable Output (b5.0V tob15V)

TL/H/7785– 8

*Optional. Improves transient

V

OUT

eb

5V

#

R1aR2

R2

J

response and ripple rejection.

4

Physical Dimensions inches (millimeters)

Metal Can Package (K)
Order Number LM345K-5.0
NS Package Number K02A

5

LM145/LM345 Negative Three Amp Regulator

Physical Dimensions inches (millimeters) (Continued)

Metal Can Package (K)

Mil-Aero Products

Order Number LM145K-5.0/883 or SMD

Ý

5962-9064501

NS Package Number K02C

LIFE SUPPORT POLICY

NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL
SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or 2. A critical component is any component of a life
systems which, (a) are intended for surgical implant support device or system whose failure to perform can
into the body, or (b) support or sustain life, and whose be reasonably expected to cause the failure of the life
failure to perform, when properly used in accordance support device or system, or to affect its safety or
with instructions for use provided in the labeling, can effectiveness.
be reasonably expected to result in a significant injury
to the user.

National Semiconductor National Semiconductor National Semiconductor National Semiconductor
Corporation Europe Hong Kong Ltd. Japan Ltd.

1111 West Bardin Road Fax: (

a

49) 0-180-530 85 86 13th Floor, Straight Block, Tel: [phone]
Arlington, TX 76017 Email: [e-mail] Ocean Centre, 5 Canton Rd. Fax: [phone]
Tel: [phone] Deutsch Tel: (

a

49) 0-180-530 85 85 Tsimshatsui, Kowloon
Fax: [phone] English Tel: (

a

49) 0-180-532 78 32 Hong Kong

Fran3ais Tel: (

a

49) 0-180-532 93 58 Tel: [phone]

Italiano Tel: (

a

49) 0-180-534 16 80 Fax: [phone]

National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.