LM48860 Datasheet, PDF (1/18 Pages) National Semiconductor (TI) – Ground-Referenced, Ultra Low Noise, Fixed Gain Stereo Headphone Amplifier

October 17, 2008
LM48860
Ground-Referenced, Ultra Low Noise, Fixed Gain Stereo
Headphone Amplifier
General Description
The LM48860 is a ground referenced, fixed-gain audio power
amplifier capable of delivering 40mW per channel of contin-
uous average power into a 16Ω single-ended load with less
than 1% THD+N from a 3V power supply.
The LM48860 features a new circuit technology that utilizes
a charge pump to generate a negative reference voltage. This
allows the outputs to be biased about ground, thereby elimi-
nating output-coupling capacitors typically used with normal
single-ended loads.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. The LM48860 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 LM48860 features a low-power consumption shutdown
mode selectable for either channel separately. This is accom-
plished by driving either the SD_RC (Shutdown Right Chan-
nel) or SD_LC (Shutdown Left Channel) (or both) pins with
logic low, depending on which channel is desired shutdown.
Additionally, the LM48860 features an internal thermal shut-
down protection mechanism.
The LM48860 contains advanced pop & click circuitry that
eliminates noises which would otherwise occur during turn-on
and turn-off transitions.
The LM48860 has an internal fixed gain of 1.5V/V.
Key Specifications
■ PSRR at 217Hz (V_DD = 3.0V)
■ Stereo Power Output at V_DD = 3V
R_L = 16Ω, THD+N = 1%
■ Shutdown Current
■ Internal Fixed Gain
■ Operating Voltage
80dB (typ)
40mW (typ)
0.1μA (typ)
1.5V/V (typ)
2.0V to 5.5V
Features
■ ^{Fixed logic levels with supply voltage}
■ ^{Ground referenced outputs}
■ ^{High PSRR}
■ ^{Available in space-saving micro SMD package}
■ ^{Ultra low current shutdown mode}
■ ^{Improved pop & click circuitry eliminates noises during}
turn-on and turn-off transitions
■ ^{No output coupling capacitors, snubber networks,}
bootstrap capacitors, or gain-setting resistors required
■ ^{Shutdown either channel independently}
Applications
■ ^{Mobile Phones}
■ ^{MP3 Players}
■ ^PDAs
■ ^{Portable electronic devices}
■ ^{Notebook PCs}
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2008 National Semiconductor Corporation 300068
www.national.com