LM4838 Stereo 2W Audio Power Amplifiers with DC Volume Control and Selectable Gain
January 2003
LM4838
Stereo 2W Audio Power Amplifiers
with DC Volume Control and Selectable Gain
General Description
The LM4838 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 LM4838 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 LM4838 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 LM4838LQ and
LM4838MTE will deliver 2W into 4Ω. The LM4838MT and LM4838ITL will
deliver 1.1W into 8Ω. See
Application Information
section
Exposed-DAP
package PCB Mounting Considerations
for more information.
Note 2:
An LM4838LQ and LM4838MTE that have 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
n
into 3Ω (LQ & MTE)
n
into 4Ω (LQ & MTE)
n
into 8Ω (MT, MTE, ITL, & LQ)
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
n
n
n
n
n
n
DC Volume Control Interface
System Beep Detect
Stereo switchable bridged/single-ended power amplifiers
Selectable internal/external gain and bass boost
“Click and pop” suppression circuitry
Thermal shutdown protection circuitry
Applications
n
Portable and Desktop Computers
n
Multimedia Monitors
n
Portable Radios, PDAs, and Portable TVs
Block Diagram
20013301
FIGURE 1. LM4838 Block Diagram
Boomer
®
is a registered trademark of NationalSemiconductor Corporation.
© 2003 National Semiconductor Corporation
DS200133
www.national.com
NSC [ NATIONAL SEMICONDUCTOR ]
