LM4894

1 Watt Fully Differential Audio Power Amplifier With

Shutdown Select

General Description

The LM4894 is a fully differential audio power amplifier

primarily designed for demanding applications in mobile

phones and other portable communication device applica-

tions. It is capable of delivering 1 watt of continuous average

power to an 8

Ω BTL load with less than 1% distortion

(THD+N) from a 5V

Boomer audio power amplifiers were designed specifically to

provide high quality output power with a minimal amount of

external components. The LM4894 does not require output

coupling capacitors or bootstrap capacitors, and therefore is

ideally suited for mobile phone and other low voltage appli-

cations where minimal power consumption is a primary re-

quirement.

The LM4894 features a low-power consumption shutdown

mode. To facilitate this, Shutdown may be enabled by either

logic high or low depending on mode selection. Driving the

shutdown mode pin either high or low enables the shutdown

select pin to be driven in a likewise manner to enable Shut-

down. Additionally, the LM4894 features an internal thermal

shutdown protection mechanism.

The LM4894 contains advanced pop & click circuitry which

eliminates noises which would otherwise occur during

turn-on and turn-off transitions.

The LM4894 is unity-gain stable and can be configured by

external gain-setting resistors.

Key Specifications

80dB(typ)

1.0W(typ)

400mW(typ)

0.1µA(typ)

Features

n

Fully differential amplification

n

Available in space-saving packages micro SMD, MSOP,

and LLP

n

Ultra low current shutdown mode

n

Can drive capacitive loads up to 500pF

n

Improved pop & click circuitry eliminates noises during

turn-on and turn-off transitions

n

2.2 - 5.5V operation

n

No output coupling capacitors, snubber networks or

bootstrap capacitors required

n

Unity-gain stable

n

External gain configuration capability

n

Shutdown high or low selectivity

n

High CMRR

Applications

n

Mobile phones

n

PDAs

n

Portable electronic devices

Connection Diagrams

Mini Small Outline (MSOP) Package

LLP Package

20013723

Top View

Order Number LM4894MM

See NS Package Number MUB10A

20013735

Top View

Order Number LM4894LD

See NS Package Number LDA10B

June 2003

© 2003 National Semiconductor Corporation

DS200137

www.national.com