LM4900

265mW at 3.3V Supply Audio Power Amplifier with

Shutdown Mode

General Description

The LM4900 is a bridged audio power amplifier capable of

delivering 265mW of continuous average power into an 8

Ω

load with 1% THD+N from a 3.3V power supply.

to provide high quality output power from a low supply volt-

age while requiring a minimal amount of external compo-

nents. Since the LM4900 does not require output coupling

capacitors, bootstrap capacitors or snubber networks, it is

optimally suited for low-power portable applications.

The LM4900 features an externally controlled, low power

consumption shutdown mode, and thermal shutdown protec-

tion.

The closed loop response of the unity-gain stable LM4900

can be configured by external gain-setting resistors.

Key Specifications

average output power into 8

Ω,

V

1.0% (max)

average output power into 8

Ω,

V

1.0% (max)

0.1µA (typ)

Features

n

MSOP, LLP, and SOP packaging

n

No output coupling capacitors, bootstrap capacitors, or

snubber circuits are necessary

n

Thermal shutdown protection circuitry

n

Unity-gain stable

n

External gain configuration capability

n

Latest generation ’click and pop’ suppression circuitry

Applications

n

Cellular phones

n

PDA’s

n

Any portable audio application

Typical Application

DS200064-1

FIGURE 1. Typical Audio Amplifier Application Circuit

September 2001

© 2001 National Semiconductor Corporation

DS200064

www.national.com