LM4982 Datasheet, PDF (1/21 Pages) National Semiconductor (TI) – Ground-Referenced, Ultra Low Noise, 80mW Stereo Headphone Amplifier with IntelliSense and I2C Volume

February 2006
LM4982
Ground-Referenced, Ultra Low Noise, 80mW Stereo
Headphone Amplifier with IntelliSense and I2C Volume
Control
General Description
The LM4982 is a ground referenced, variable gain audio
power amplifier capable of delivering 80mW of continuous
average power into a 16Ω single-ended load with less than
1% THD+N from a 3V power supply. The I²C volume control
allows +18 to -76 dB gain settings.
The LM4982 utilizes advanced charge pump technology to
generate the LM4982’s negative supply voltage. This elimi-
nates the need for output-coupling capacitors typically used
with single-ended loads.
IntelliSense is a new circuit technology that allows the
LM4982 to detect whether a mono or stereo headphone plug
has been inserted into the output jack.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. The LM4982 does not require output
coupling capacitors or bootstrap capacitors, and therefore is
ideally suited for mobile phone and other low voltage appli-
cations where minimal power consumption is a primary re-
quirement.
The LM4982 incorporates selectable low-power consump-
tion shutdown and channel select modes.
The LM4982 contains advanced pop & click circuitry that
eliminates noises which would otherwise occur during
turn-on and turn-off transitions.
Key Specifications
j Improved PSRR at 217Hz
j Stereo Output Power at V_DD = 3V,
R_L = 32Ω, THD+N = 1%
j Shutdown current
66dB
51mW (typ)
0.1µA (typ)
Features
n Ground referenced outputs
n I²C Volume and mode controls
n Available in space-saving micro SMD package
n Ultra low current shutdown mode
n Advanced pop & click circuitry eliminates noises during
turn-on and turn-off transitions
n 1.6 – 4.0V operation
n No output coupling capacitors, snubber networks,
bootstrap capacitors or gain-setting resistors required
n Mono/Stereo headphone detect
Applications
n Notebook PCs
n Desktop PCs
n Mobile Phones
n PDAs
n Portable electronic devices
n MP3 Players
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2006 National Semiconductor Corporation DS201614
www.national.com