LM49120 Datasheet, PDF (1/28 Pages) National Semiconductor (TI) – Audio Sub-System with Mono Class AB Loudspeaker Amplifier and Stereo OCL/SE Headphone Amplifier

July 15, 2008
LM49120
Audio Sub-System with Mono Class AB Loudspeaker
Amplifier and Stereo OCL/SE Headphone Amplifier
General Description
The LM49120 is a compact audio subsystem designed for
portable handheld applications such as cellular phones. The
LM49120 combines a mono 1.3W speaker amplifier, stereo
85mW/ch output capacitorless headphone amplifier, 32 step
volume control, and an input mixer/multiplexer into a single
16–bump micro SMD package.
The LM49120 has three input channels: two single-ended
stereo inputs and a differential mono input. Each input fea-
tures a 32-step digital volume control. The headphone output
stage features an 8 step (-18dB – 0dB) attenuator, while the
speaker output stage has two selectable (0dB/+6dB) gain
settings. The digital volume control and mode control are pro-
grammed through a two-wire I²C compatible interface.
Key Specifications
■ Output power at V_DD = 5V:
 Speaker:
  R_L = 8Ω BTL, THD+N ≤ 1%
 Headphone:
  R_L = 32Ω, SE, THD+N ≤ 1%
■ Output power at V_DD = 3.6V:
 Speaker:
  R_L = 8Ω, BTL, THD+N ≤ 1%
■ Output power at V_DD = 3.3V:
1.3W (typ)
85mW (typ)
632mW (typ)
 Speaker:
  R_L = 8Ω, BTL, THD+N ≤ 1%
 Headphone:
  R_L = 32Ω, OCL/SE, THD+N ≤ 1%
540mW (typ)
35mW (typ)
Features
■ ^{RF immunity}
■ ^{Selectable OCL/SE headphone drivers}
■ ^{32 Step volume control}
■ ^{Click and Pop suppression}
■ ^{Independent speaker and headphone gain settings}
■ ^{Minimum external components}
■ ^{Thermal over load protection}
■ ^{Micro-power shutdown}
■ ^{Space saving 16–bump mciro SMD package}
■ ^{Thermal shutdown protection}
■ ^{Micro-power shutdown}
■ ^{I2C Control Interface}
Applications
■ ^{Mobile Phones}
■ ^PDAs
■ ^{Portable Electronics}
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