LM4855 Datasheet, PDF (1/24 Pages) National Semiconductor (TI) – Boomer AUDIO POWER AMPLIFIER Integrated Audio Amplifier System

November 2002
LM4855
Integrated Audio Amplifier System
General Description
The LM4855 is an audio power amplifier system capable of
delivering 1.1W (typ) of continuous average power into a
mono 8Ω bridged-tied load (BTL) with 1% THD+N and
115mW (typ) per channel of continuous average power into
stereo 32Ω BTL loads with 0.5% THD+N, using a 5V power
supply.
The LM4855 features a 32 step digital volume control and
eight distinct output modes. The digital volume control and
output modes are programmed through a three-wire SPI
serial control interface, that allows flexibility in routing and
mixing audio channels.
The LM4855 is designed for cellular phone, PDA, and other
portable handheld applications. It delivers high quality output
power from a surface-mount package and requires only six
external components.
The industry leading micro SMD package only utilizes 2mm
x 2.3mm of PCB space, making the LM4855 the most space
efficient audio sub system available today.
Key Specifications
n THD+N at 1kHz, 1.1W into 8Ω BTL
n THD+N at 1kHz, 115mW into 32Ω BTL
n Single Supply Operation
1.0% (typ)
0.5% (typ)
2.6 to 5.0V
Features
n 1.1W (typ) output power with 8Ω mono BTL load
n 115mW (typ) output power with stereo 32Ω BTL loads
n SPI programmable 32 step digital volume control
n Eight distinct output modes
n micro-SMD and LLP surface mount packaging
n "Click and Pop" suppression circuitry
n Thermal shutdown protection
n Low shutdown current (0.1uA, typ)
Applications
n Moblie Phones
n PDAs
Typical Application
FIGURE 1. Typical Audio Amplifier Application Circuit
200395D1
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© 2002 National Semiconductor Corporation DS200395
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