LM4881

Dual 200 mW Headphone Amplifier with Shutdown Mode

General Description

The LM4881 is a dual audio power amplifier capable of deliv-

ering 200 mW of continuous average power into an 8

Ω load

with 0.1% (THD) from a 5V power supply.

Boomer audio power amplifiers were designed specifically to

provide high quality output power with a minimal amount of

external components using surface mount packaging. Since

the LM4881 does not require bootstrap capacitors or snub-

ber networks, it is optimally suited for low-power portable

systems.

The LM4881 features an externally controlled, low power

consumption shutdown mode which is virtually clickless and

popless, as well as an internal thermal shutdown protection

mechanism.

The unity-gain stable LM4881 can be configured by external

gain-setting resistors.

Key Specifications

n THD at 1 kHz at 125 mW

continuous average output

power into 8

Ω

0.1% (max)

n THD at 1 kHz at 75 mW continuous

average output power into 32

Ω

0.02% (typ)

n Output power at 10% THD+N

at 1 kHz into 8

Ω

300 mW (typ)

n Shutdown Current

0.7 µA (typ)

Features

n MSOP surface mount packaging

n Unity-gain stable

n External gain configuration capability

n Thermal shutdown protection circuitry

n No bootstrap capacitors, or snubber circuits are

necessary

Applications

n Headphone Amplifier

n Personal Computers

n Microphone Preamplifier

Typical Application

Connection Diagrams

DS100005-1

*Refer to the Application Information Section for information concerning

proper selection of the input and output coupling capacitors.

FIGURE 1. Typical Audio Amplifier Application Circuit

MSOP Package

DS100005-2

SOP and DIP Package

DS100005-38

Top View

Order Number LM4881MM, LM4881M, or LM4881N

See NS Package Number MUA08A, M08A, or N08E

September 1997

© 1999 National Semiconductor Corporation

DS100005

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