LM4832 Digitally Controlled Tone and Volume Circuit with Stereo Audio Power Amplifier,
Microphone Preamp Stage and National 3D Sound
February 1998
LM4832
Digitally Controlled Tone and Volume Circuit with Stereo
Audio Power Amplifier, Microphone Preamp Stage and
National 3D Sound
General Description
The LM4832 is a monolithic integrated circuit that provides
volume and tone (bass and treble) controls as well as a ste-
reo audio power amplifier capable of producing 250 mW
(typ) into 8Ω or 90 mW (typ) into 32Ω with less than 1.0%
THD. In addition, a two input microphone preamp stage, with
volume control, capable of driving a 1 kΩ load is imple-
mented on chip.
The LM4832 also features National’s 3D Sound circuitry
which can be externally adjusted via a simple RC network.
For maximum system flexibility, the LM4832 has an exter-
nally controlled, low-power consumption shutdown mode,
and an independent mute for power and microphone ampli-
fiers .
audio integrated circuits were designed specifically
to provide high quality audio while requiring few external
components. Since the LM4832 incorporates tone and vol-
ume controls, a stereo audio power amplifier and a micro-
phone preamp stage, it is optimally suited to multimedia
monitors and desktop computer applications.
Boomer
®
Key Specifications
n
Output Power at 10% into:
8Ω
32Ω
n
THD + N at 75 mW into
32Ω at 1 kHz
n
Microphone Input Referred
Noise
n
Supply Current
n
Shutdown Current
350 mW(typ)
100 mW(typ)
0.5%(max)
7 µV(typ)
13 mA(typ)
4 µA(max)
Features
n
n
n
n
n
n
Independent Left and Right Output Volume Controls
Treble and Bass Control
National 3D Sound
I
2
C Compatible Interface
Two Microphone Inputs with Selector
Software Controlled Shutdown Function
Applications
n
Multimedia Monitors
n
Portable and Desktop Computers
Block Diagram
Connection Diagram
DS100014-2
DS100014-1
FIGURE 1. LM4832 Block Diagram
Top View
Order Number LM4832N, LM4832M
See NS Package Number N28B for DIP
See NS Package Number M28B for SOIC
Boomer
®
is a registered trademark of National Semiconductor Corporation.
© 1998 National Semiconductor Corporation
DS100014
www.national.com
NSC [ NATIONAL SEMICONDUCTOR ]
