LM4897

1.1 Watt Audio Power Amplifier with Fade-In and

Fade-Out

General Description

The LM4897 is an audio power amplifier primarily designed

for demanding applications in mobile phones and other por-

table communication device applications. It is capable of

delivering 1.1W of continuous average power to an 8

Ω BTL

load with less than 1% distortion (THD+N) from a +5V

DC

power supply.

The LM4897 contains advanced pop and click circuitry that

eliminate noises which would otherwise occur during turn-on

and turn-off transitions. It also contains a fade-in/fade-out

feature that eliminates unnatural sound generated by

asserting/de-asserting the SHUTDOWN pin. The LM4897 is

unity-gain stable and can be configured by external gain-

setting resistors.

The LM4897 features a low-power consumption global shut-

down mode, which is achieved by driving the shutdown pin

with logic low. Additionally, the LM4897 features an internal

thermal shutdown protection mechanism.

Boomer audio power amplifiers were designed specifically to

provide high quality output power with a minimal amount of

external components. The LM4897 does not require output

coupling capacitors or bootstrap capacitors, and therefore is

ideally suited for lower-power portable applications where

minimal space and power consumption are primary require-

ments.

Key Specifications

62dB (typ)

1.1W (typ)

350mW (typ)

0.1µA (typ)

Features

n

No output coupling capacitors, snubber networks or

bootstrap capacitors required

n

Unity gain stable

n

Ultra low current shutdown mode

n

Fade-In/Fade-Out

n

BTL output can drive capacitive loads up to 100pF

n

Advanced pop and click circuitry eliminates noises

during turn-on and turn-off transitions

n

2.6V - 5.5V operation

n

Available in a space-saving SO package

Applications

n

Mobile Phones

n

PDAs

n

Portable electronic devices

Connection Diagrams

Mini Small Outline (MSOP) Package

MSOP Marking

20050930

Top View

Order Number LM4897MM

See NS package Number MUB10A

200509D0

Top View

G - Boomer Family

97 - LM4897MM

May 2003

© 2003 National Semiconductor Corporation

DS200509

www.national.com