LM49100_0709 Datasheet, PDF (1/26 Pages) National Semiconductor (TI) – Mono Class AB Audio Sub-System with a True-Ground Headphone Amplifier

September 2007
LM49100
Mono Class AB Audio Sub-System with a True-Ground
Headphone Amplifier
General Description
The LM49100 is a fully integrated audio subsystem capable
of delivering 1.275W of continuous average power into a
mono 8Ω bridged-tied load (BTL) with 1% THD+N and with a
5V power supply. The LM49100 also has a stereo true-ground
headphone amplifier capable of 50mW per channel of con-
tinuous average power into a 32Ω single-ended (SE) loads
with 1% THD+N.
The LM49100 has three input channels. One pair of SE inputs
can be used with a stereo signal. The other input channel is
fully differential and may be used with a mono input signal.
The LM49100 features a 32-step digital volume control and
ten distinct output modes. The mixer, volume control, and de-
vice mode select are controlled through an I²C compatible
interface.
Thermal overload protection prevent the device from being
damaged during fault conditions. Superior click and pop sup-
pression eliminates audible transients on power-up/down and
during shutdown.
Key Specifications
■ Power Output at V_DD = 5V:
  Loudspeaker (LS):
R_L = 8Ω, THD+N ≤ 1%
  Headphone (V_DDHP = 2.8V):
R_L = 32Ω, THD+N ≤ 1%
■ Shutdown current
1.275W
50mW
0.01µA
Features
■ ^{Mono and stereo inputs}
■ ^{Thermal Overload Protection}
■ ^{True-ground Headphone Drivers}
■ ^{I2C Control Interface}
■ ^{Input mute attenuation}
■ ^{2nd Stage headphone attenuator}
■ ^{32-step digital volume control}
■ ^{10 Operating Modes}
■ ^{Minimum external components}
■ ^{Click and Pop suppression}
■ ^{Micro-power shutdown}
■ ^{Available in space-saving 3mm x 3mm 25 bump GR}
package
■ ^{RF Suppression}
Applications
■ ^{Mobile Phones}
■ ^PDAs
■ ^Laptops
■ ^{Portable Electronics}
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