LM4835

Stereo 2W Audio Power Amplifiers

with DC Volume Control and Selectable Gain

General Description

The LM4835 is a monolithic integrated circuit that provides

DC volume control, and stereo bridged audio power amplifi-

ers capable of producing 2W into 4

Ω (Note 1) with less than

1.0% THD or 2.2W into 3

Ω (Note 2) with less than 1.0%

THD.

to provide high quality audio while requiring a minimum

amount of external components. The LM4835 incorporates a

DC volume control, stereo bridged audio power amplifiers

and a selectable gain or bass boost, making it optimally

suited for multimedia monitors, portable radios, desktop, and

portable computer applications.

The LM4835 features an externally controlled, low-power

consumption shutdown mode, and both a power amplifier

and headphone mute for maximum system flexibility and

performance.

Note 1: When properly mounted to the circuit board, the LM4835MTE will

deliver 2W into 4

Ω. The LM4835MT will deliver 1.1W into 8Ω. See the Appli-

cation Information section for LM4835MTE usage information.

Note 2: An LM4835MTE which has been properly mounted to the circuit

board and forced-air cooled will deliver 2.2W into 3

Ω.

Key Specifications

into 3

Ω (LM4835MTE)

2.2W(typ)

into 4

Ω (LM4835MTE)

2.0W(typ)

into 8

Ω (LM4835)

1.1W(typ)

n Single-ended mode - THD+N

at 85mW into 32

Ω

1.0%(typ)

n Shutdown current

0.7µA(typ)

Features

n PC98 Compliant

n DC Volume Control Interface

n System Beep Detect

n Stereo switchable bridged/single-ended power amplifiers

n Selectable internal/external gain and bass boost

configurable

n “Click and pop” suppression circuitry

n Thermal shutdown protection circuitry

Applications

n Portable and Desktop Computers

n Multimedia Monitors

n Portable Radios, PDAs, and Portable TVs

Block Diagram

Connection Diagram

DS100139-1

FIGURE 1. LM4835 Block Diagram

TSSOP Package

DS100139-2

Top View

Order Number LM4835MT

See NS Package Number MTC28 for TSSOP

Order Number LM4835MTE

See NS Package Number MXA28A for Exposed DAP

TSSOP

March 1999

© 1999 National Semiconductor Corporation

DS100139

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