LM4865

750 mW Audio Power Amplifier with DC Volume Control

and Headphone Switch

General Description

The LM4865 is a mono bridged audio power amplifier with

DC volume control, capable of delivering 750 mW of continu-

ous average power into an 8

Ω load with less than 1% THD

from a 5V power supply. Switching between bridged speaker

mode and headphone (single ended) mode is accomplished

via a headphone sense pin. In addition, LM4865 is set into

low current consumption shutdown mode (0.7 µA typical) by

lowering the DC Vol/SD pin to below 0.3V.

Boomer audio power amplifiers are designed specifically to

provide high power audio output, with quality sound, from a

low supply voltage source while requiring the minimal

amount of external components.

Applications

n GSM phones and accessories, DECT, office phones

n Hand held radio

n Other portable audio devices

Key Specifications

n Shutdown Current: 0.7 µA (typ)

Features

n DC volume control

n Headphone amplifier mode

n “Click and pop” suppression

n Shutdown control when volume control pin is low

n Thermal shutdown protection

Typical Application

Connection Diagram

DS101025-1

FIGURE 1. Typical Audio Amplifier

Application Circuit

MSOP, SOP Package

DS101025-2

Top View

Order Number LM4865M, LM4865MM

See NS Package Number M08A, MUA08A

December 1999

© 1999 National Semiconductor Corporation

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