LM4811

Dual 105mW Headphone Amplifier with Digital Volume

Control and Shutdown Mode

General Description

The LM4811 is a dual audio power amplifier capable of

delivering 105mW per channel of continuous average power

into a 16

Ω load with 0.1% (THD+N) 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. Since the LM4811 does not require

bootstrap capacitors or snubber networks, it is optimally

suited for low-power portable systems.

The LM4811 features a digital volume control that sets the

amplifier’s gain from +12dB to −33dB in 16 discrete steps

using a two−wire interface.

The unity-gain stable LM4811 also features an externally

controlled, active-high, micropower consumption shutdown

mode. It also has an internal thermal shutdown protection

mechanism.

Key Specifications

n

THD+N at 1kHz, 105mW continuous average output

power into 16

Ω

0.1% (typ)

n

THD+N at 1kHz, 70mW continuous average power into

32

Ω

0.1% (typ)

n

Shutdown Current

0.3µA (typ)

Features

n

Digital volume control range from +12dB to −33dB

n

LD and MSOP surface mount packaging

n

"Click and Pop" suppression circuitry

n

No bootstrap capacitors required

n

Low shutdown current

Applications

n

Cellular Phones

n

MP3, CD, DVD players

n

PDA’s

n

Portable electronics

Connection Diagrams

MSOP Package

20006102

Top View

Order Number LM4811MM

See NS Package Number MUB10A

LD Package

20006162

Top View

Order Number LM4811LD

See NS Package Number LDA10A

December 2002

© 2002 National Semiconductor Corporation

DS200061

www.national.com