LM4871

3W Audio Power Amplifier with Shutdown Mode

General Description

The LM4871 is a mono bridged audio power amplifier ca-

pable of delivering 3W of continuous average power into a

3

Ω load with less than 10% THD when powered by a 5V

power supply (Note 1). To conserve power in portable appli-

cations, the LM4871’s micropower shutdown mode (I

0.6µA, typ) is activated when V

DOWN pin.

Boomer audio power amplifiers are designed specifically to

provide high power, high fidelity audio output. They require

few external components and operate on low supply volt-

ages from 2.0V to 5.5V. Since the LM4871 does not require

output coupling capacitors, bootstrap capacitors, or snubber

networks, it is ideally suited for low-power portable systems

that require minimum volume and weight.

Additional LM4871 features include thermal shutdown pro-

tection, unity-gain stability, and external gain set.

Note 1: An LM4871LD that has been properly mounted to a circuit board will

deliver 3W into 3

Ω (at 10% THD). The other package options for the LM4871

will deliver 1.5W into 8

Ω (at 10% THD). See the Application Information

sections for further information concerning the LM4871LD, LM4871MM,

LM4871M, and the LM4871N.

Key Specifications

n

PO at 10% THD+N, 1kHz

n

LM4871LD: 3

Ω ,4Ω loads

3W (typ), 2.5W (typ)

n

All other LM4871 packages: 8

Ω load

1.5W (typ)

n

Shutdown current

0.6µA (typ)

n

Supply voltage range

2.0V to 5.5V

n

THD at 1kHz at 1W continuous average output power

into 8

Ω

0.5% (max)

Features

n

No output coupling capacitors, bootstrap capacitors, or

snubber circuits required

n

Unity-gain stable

n

LLP, MSOP, SO, or DIP packaging

n

External gain configuration capability

n

Pin compatible with the LM4861

Applications

n

Portable computers

n

Desktop computers

n

Low voltage audio systems

Connection Diagrams

MSOP, Small Outline, and DIP Package

LLP Package

10000802

Top View

Order Number LM4871MM, LM4871M, or LM4871N

See NS Package Number MUA08A, M08A, or N08E

10000839

Top View

Order Number LM4871LD

See NS Package Number LDC08A

January 2003

© 2004 National Semiconductor Corporation

DS100008

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