NSC LM384N Datasheet

LM384
5W Audio Power Amplifier

General Description

The LM384 is a power audio amplifier for consumer applica­tion. In order to holdsystemcostto a minimum, gain is inter­nally fixed at 34 dB. A unique input stage allows inputs to be
ground referenced. The output is automatically
self-centering to one half the supply voltage.

The output is short-circuit proof with internal thermal limiting.
The package outline is standard dual-in-line. A copper lead
frame is used with the center three pins on either side com­prising a heat sink. This makes the device easy to use in
standard p-c layout.

Uses include simple phonograph amplifiers, intercoms, line
drivers, teaching machine outputs, alarms, ultrasonic driv­ers, TV sound systems, AM-FM radio, sound projector sys­tems, etc. See AN-69 for circuit details.

Features

n Wide supply voltage range
n Low quiescent power drain
n Voltage gain fixed at 50
n High peak current capability
n Input referenced to GND
n High input impedance
n Low distortion
n Quiescent output voltage is at one half of the supply

voltage

n Standard dual-in-line package

Schematic Diagram

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February 1995

LM384 5W Audio Power Amplifier

© 1999 National Semiconductor Corporation DS007843 www.national.com

Absolute Maximum Ratings (Note 1)

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

Supply Voltage 28V
Peak Current 1.3A
Power Dissipation (See (Notes 4, 5)) 1.67W
Input Voltage

±

0.5V

Storage Temperature −65˚C to +150˚C

Operating Temperature 0˚C to +70˚C
Lead Temperature

(Soldering, 10 sec.) 260˚C

Thermal Resistance

θ

JC

30˚C/W

θ

JA

79˚C/W

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to
the device may occur. Operating Ratings indicate conditions for which the de­vice is functional, but do not guarantee specific performance limits.

Electrical Characteristics (Note 2)

Symbol Parameter Conditions Min Typ Max Units

Z

IN

Input Resistance 150 kΩ

I

BIAS

Bias Current Inputs Floating 100 nA

A

V

Gain 40 50 60 V/V

P

OUT

Output Power THD=10%,R

L

=

8Ω 5 5.5 W

I

Q

Quiescent Supply Current 8.5 25 mA

V

OUT Q

Quiescent Output Voltage 11 V

BW Bandwidth P

OUT

=

2W, R

L

=

8Ω 450 kHz

V

+

Supply Voltage 12 26 V

I

SC

Short Circuit Current (Note 6) 1.3 A

PSRR

RTO

Power Supply Rejection Ratio 31 dB
(Note 3) )

THD Total Harmonic Distortion P

OUT

=

4W, R

L

=

8Ω 0.25 1.0

%

Note 2: V

+

=

22V and T

A

=

25˚C operating with a Staver V7 heat sink for 30 seconds.

Note 3: Rejection ratio referred to the output with C

BYPASS

=

5 µF, freq=120 Hz.

Note 4: The maximum junction temperature of the LM384 is 150˚C.
Note 5: The package is to be derated at 15˚C/W junction to heat sink pins.
Note 6: Output is fully protected against a shorted speaker condition at all voltages up to 22V.

Heat Sink Dimensions

Staver “V7” Heat Sink

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Staver Company
41 Saxon Ave.
P.O. Drawer H
Bay Shore, N.Y.
Tel: [phone]

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Typical Performance Characteristics

Device Dissipation vs
Ambient Temperature

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Thermal Resistance vs
Square Inches

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Supply Decoupling vs
Frequency

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Total Harmonic Distortion
vs Output Power

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Output Voltage Gain vs
Frequency

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Total Harmonic Distortion
vs Frequency

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Power Supply Current vs
Supply Voltage

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Device Dissipation vs
Output Power — 16Ω Load

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Device Dissipation vs
Output Power — 8Ω Load

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