LM4831 Multimedia Computer Audio Chip
November 1998
LM4831
Multimedia Computer Audio Chip
General Description
The LM4831 is a monolithic integrated circuit that provides a
stereo three input mixer, two stereo input analog multiplexer,
a stereo line out and a dual 1W bridged audio power ampli-
fier. In addition, a low noise microphone preamp is included
on-chip.
The LM4831 is ideal for multimedia computers since it incor-
porates an input mixer, analog multiplexer, and configurable
stereo audio power amplifier, as well as a microphone
preamp stage. This combination allows for all of the analog
audio processing to be enclosed in a 44-pin TQFP package.
The LM4831 features an externally controlled, low-power
consumption shutdown mode, as well as both headphone
and docking station modes. To temporarily override the shut-
down mode and allow audio signals to be amplified, the
LM4831 provides four 鈥渂eep鈥?pins.
Key Specifications
n
THD+N at 1W into 8鈩?/div>
n
Microphone Input Referred Noise
n
Supply Current - Bridged Mode
n
Shutdown Current
0.6% (typ)
10碌V (typ)
16mA (typ)
2碌A(chǔ) (typ)
Features
Stereo 1W audio power amplifier
鈥淐lick and pop鈥?suppression circuitry
Stereo three input mixer
Shutdown mode
Multiple operating modes 鈥?bridged, single-ended and
docking station modes
n
Internal mux for switching in/out external filter
n
Beep circuitry for 鈥渨ake-up鈥?while in shutdown
n
44 Pin TQFP Packaging
n
n
n
n
n
Applications
n
Portable and Desktop Computers
Block Diagram
Connection Diagram
DS100057-1
FIGURE 1. LM4831 Block Diagram
DS100057-3
Top View
Order Number LM4831VF
See NS Package Number VEJ44A
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is a registered trademark of National Semiconductor Corporation.
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is a registered trademark of National Semiconductor Corporation.
漏 1998 National Semiconductor Corporation
DS100057
www.national.com
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