March 1999
LM4835
Stereo 2W Audio Power Amplifiers
with DC Volume Control and Selectable Gain
General Description
Key Specifications
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
n PO at 1% THD+N
into 3Ω (LM4835MTE)
into 4Ω (LM4835MTE)
into 8Ω (LM4835)
2.2W(typ)
2.0W(typ)
1.1W(typ)
1.0%(typ)
n Single-ended mode - THD+N
at 85mW into 32Ω
n Shutdown current
0.7µA(typ)
suited for multimedia monitors, portable radios, desktop, and Features
portable computer applications.
n PC98 Compliant
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.
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
Note 2: An LM4835MTE which has been properly mounted to the circuit
board and forced-air cooled will deliver 2.2W into 3Ω.
Applications
n Portable and Desktop Computers
n Multimedia Monitors
n Portable Radios, PDAs, and Portable TVs
Block Diagram
Connection 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
DS100139-1
FIGURE 1. LM4835 Block Diagram
Boomer® is a registered trademark of NationalSemiconductor Corporation.
© 1999 National Semiconductor Corporation
DS100139
www.national.com
NSC [ National Semiconductor ]
