LM4954

High Voltage 3 Watt Audio Power Amplifier

General Description

The LM4954 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 2.4 Watts of continuous average power to an 8

Ω

BTL load with less than 1% THD+N from a 7V

supply.

Boomer audio power amplifiers are designed specifically to

provide high quality output power with a minimal number of

external components. The LM4954 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.

The LM4954 features a low-power consumption global shut-

down mode which is achieved by driving the shutdown pin

with logic low. Additionally, the LM4954 features an internal

thermal shutdown protection mechanism.

The LM4954 contains advanced pop & click circuitry which

eliminates noises that would otherwise occur during turn-on

and turn-off transitions.

The LM4954 is unity-gain stable and can be configured by

external gain-setting resistors.

Key Specifications

Voltage Range

2.7

≤ V

DD

≤ 9V

2.4W (typ)

3mA (typ)

80dB (typ)

0.01µA (typ)

Features

n

No output coupling capacitors, snubber networks or

bootstrap capacitors required

n

Unity gain stable

n

Externally configurable gain

n

Ultra low current active low shutdown mode

n

BTL output can drive capacitive loads up to 100pF

n

“Click and pop” suppression circuitry

n

2.7V - 9.0V operation

n

Available in space-saving microSMD package

Applications

n

Mobile Phones

n

PDAs

Typical Application

20129111

FIGURE 1. Typical Audio Amplifier Application Circuit

June 2005

© 2005 National Semiconductor Corporation

DS201291

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