May 21, 2009
LM49200
Stereo Class AB Audio Subsystem with a True Ground
Headphone Amplifier
RL = 8Ω speaker
520W (typ)
General Description
RL = 32Ω headphone
The LM49200 is a fully integrated audio subsystem with a
stereo power amplifier capable of delivering 500mW of con-
tinuous average power per channel into 8Ω with 1% THD+N
using a 3.3V supply. The LM49200 includes a separate stereo
headphone amplifier that can deliver 35mW per channel into
32Ω.
38mW (typ)
■ꢀPSRR:
ꢀꢀVDD = 3.3V, 217Hz ripple, Mono In
■ꢀShutdown power supply current
95dB (typ)
0.02μA (typ)
The LM49200 has three input channels. A pair of single-end-
ed inputs and a fully differential input channel. The LM49200
features a 32-step digital volume control on the input stage
and an 8-step digital volume control on the headphone output
stage.
Features
Differential mono input and stereo single-ended input
32-step digital volume control (-80 to +18dB)
Three independent volume channels (Left, Right, Mono)
Separate headphone volume control
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The digital volume control and output modes are programmed
through a two-wire I2C compatible interface that allows flexi-
bility in routing and mixing audio channels.
Flexible output for speaker and headphone output
True Ground headphone amplifier eliminates large DC
blocking capacitors reducing PCB space and cost
The LM49200 is designed for cellular phone, PDA, and other
portable handheld applications. The high level of integration
minimizes external components. The True Ground head-
phone amplifier eliminates the physically large DC blocking
output capacitors reducing required board space and reduc-
ing cost.
Receiver pass-through capability
Soft enable function
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RF immunity topology
“Click and Pop” suppression circuitry
Thermal shutdown protection
Micro-power shutdown
Key Specifications
■ꢀSupply Voltage (VDD
■ꢀI2C Supply Voltage
)
2.7V ≤ VDD ≤ 5.5V
1.7V ≤I2CVDD ≤5.5V
I2C control interface
Available in space-saving microSMD package
■ꢀOutput power at VDD = 5V,
ꢀꢀ1% THD+N
Applications
Portable electronic devices
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RL = 8Ω speaker
1.25W (typ)
38mW (typ)
Mobile Phones
RL = 32Ω headphone
PDAs
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■ꢀOutput power at VDD = 3.3V,
ꢀꢀ1% THD+N
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