LM4835 Stereo 2W Audio Power Amplifiers with DC Volume Control and Selectable Gain
March 1999
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 4Ω (Note 1) with less than
1.0% THD or 2.2W into 3Ω (Note 2) with less than 1.0%
THD.
Boomer
®
audio integrated circuits were designed specifically
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 4Ω. 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 3Ω.
Key Specifications
n
P
O
at 1% THD+N
into 3Ω (LM4835MTE)
into 4Ω (LM4835MTE)
into 8Ω (LM4835)
n
Single-ended mode - THD+N
at 85mW into 32Ω
n
Shutdown current
2.2W(typ)
2.0W(typ)
1.1W(typ)
1.0%(typ)
0.7µA(typ)
Features
PC98 Compliant
DC Volume Control Interface
System Beep Detect
Stereo switchable bridged/single-ended power amplifiers
Selectable internal/external gain and bass boost
configurable
n
“Click and pop” suppression circuitry
n
Thermal shutdown protection circuitry
n
n
n
n
n
Applications
n
Portable and Desktop Computers
n
Multimedia Monitors
n
Portable Radios, PDAs, and Portable TVs
Block Diagram
Connection Diagram
TSSOP Package
DS100139-2
DS100139-1
FIGURE 1. LM4835 Block Diagram
Top View
Order Number LM4835MT
See NS Package Number MTC28 for TSSOP
Order Number LM4835MTE
See NS Package Number MXA28A for Exposed DAP
TSSOP
Boomer
®
is a registered trademark of NationalSemiconductor Corporation.
© 1999 National Semiconductor Corporation
DS100139
www.national.com
NSC [ NATIONAL SEMICONDUCTOR ]
