LM4951

Wide Voltage Range 1.8 Watt Audio Amplifier

General Description

The LM4951 is an audio power amplifier primarily designed

for demanding applications in Portable Handheld devices. It

is capable of delivering 1.8W mono BTL to an 8

Ω load,

continuous average power, with less than 1% distortion

(THD+N) from a 7.5V

Boomer audio power amplifiers were designed specifically to

provide high quality output power with a minimal amount of

external components. The LM4951 does not require boot-

strap capacitors, or snubber circuits.

The LM4951 features a low-power consumption active-low

shutdown mode. Additionally, the LM4951 features an inter-

nal thermal shutdown protection mechanism.

The LM4951 contains advanced pop & click circuitry that

eliminates noises which would otherwise occur during

turn-on and turn-off transitions.

The LM4951 is unity-gain stable and can be configured by

external gain-setting resistors.

Key Specifications

2.7V to 9V

(V

2.5mA (typ)

1% THD

1.8W (typ)

0.01µA (typ)

25mS (typ)

Features

n

Pop & click circuitry eliminates noise during turn-on and

turn-off transitions

n

Low current, active-low shutdown mode

n

Low quiescent current

n

Thermal shutdown protection

n

Unity-gain stable

n

External gain configuration capability

Applications

n

Portable Handheld Devices up to 9V

n

Cell Phone

n

PDA

Typical Application

200942F4

*R

disabled when in shutdown mode, then R

FIGURE 1. Typical Bridge-Tied-Load (BTL) Audio Amplifier Application Circuit

November 2005

© 2005 National Semiconductor Corporation

DS200942

www.national.com