September 1997
LM4881
Dual 200 mW Headphone Amplifier with Shutdown Mode
General Description
Key Specifications
The LM4881 is a dual audio power amplifier capable of deliv-
ering 200 mW of continuous average power into an 8Ω load
with 0.1% (THD) from a 5V power supply.
n THD at 1 kHz at 125 mW
continuous average output
power into 8Ω
0.1% (max)
0.02% (typ)
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components using surface mount packaging. Since
the LM4881 does not require bootstrap capacitors or snub-
ber networks, it is optimally suited for low-power portable
systems.
n THD at 1 kHz at 75 mW continuous
average output power into 32Ω
n Output power at 10 THD+N
%
at 1 kHz into 8Ω
300 mW (typ)
0.7 µA (typ)
n Shutdown Current
The LM4881 features an externally controlled, low power
consumption shutdown mode which is virtually clickless and
popless, as well as an internal thermal shutdown protection
mechanism.
Features
n MSOP surface mount packaging
n Unity-gain stable
The unity-gain stable LM4881 can be configured by external
gain-setting resistors.
n External gain configuration capability
n Thermal shutdown protection circuitry
n No bootstrap capacitors, or snubber circuits are
necessary
Applications
n Headphone Amplifier
n Personal Computers
n Microphone Preamplifier
Typical Application
Connection Diagrams
MSOP Package
DS100005-2
SOP and DIP Package
DS100005-1
*Refer to the Application Information Section for information concerning
proper selection of the input and output coupling capacitors.
DS100005-38
FIGURE 1. Typical Audio Amplifier Application Circuit
Top View
Order Number LM4881MM, LM4881M, or LM4881N
See NS Package Number MUA08A, M08A, or N08E
Boomer® is a registered trademark of National Semiconductor Corporation.
© 1999 National Semiconductor Corporation
DS100005
www.national.com