May 29, 2009
LM49350
High Performance Audio Codec Sub-System with a
Ground-Referenced Stereo Headphone Amplifier & an
Ultra Low EMI Class D Loudspeaker Amplifier with Dual
I2S/PCM Digital Audio Interfaces
SNR (Stereo DAC at 48kHz)
SNR (Stereo ADC at 48kHz)
Shutdown Current
PSRR at 217 Hz, A_VDD = 3.3V, (HP from
AUX)
96dB (typ)
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1.0 General Description
94dB (typ)
2.3µA (typ)
97dB (typ)
The LM49350 is a high performance audio subsystem that
supports both analog and digital audio functions. The
LM49350 includes a high quality stereo DAC, a high quality
stereo ADC, a stereo headphone amplifier that supports
ground referenced output cap-less operation, a dual mode
earpiece speaker amplifier, and a low EMI Class D loud-
speaker amplifier. It is designed for demanding applications
in mobile phones and other portable devices.
4.0 Features
High performance 96dB SNR stereo DAC
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High performance 94dB SNR stereo ADC
The LM49350 features dual bi-directional I2S or PCM audio
interfaces for full range audio and an I2C compatible interface
for control. The stereo DAC path features an SNR of 96dB
with 24-bit 48 kHz input. The headphone amplifier delivers
69mWRMS (typ) to a 32Ω single-ended stereo load with less
than 1% distortion (THD+N) when A_VDD = 3.3V. The ear-
piece speaker amplifier delivers 58mWRMS (typ) to a 32Ω
bridged-tied load with less than 1% distortion (THD+N) when
A_VDD = 3.3V. The loudspeaker amplifier delivers up to
495mW into an 8Ω load with less than 1% distortion when
LS_VDD = 3.3V and up to 1.2W when LS_VDD = 5.0V.
Up to 192kHz stereo audio playback
Up to 48kHz stereo recording
Dual bidirectional I2S or PCM compatible audio interfaces
Read/write I2C compatible control interface
Flexible digital mixer with sample rate conversion
Dual sigma-delta PLLs for operation from any clock at any
sample rate
Digital 3D stereo enhancement
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Dual 5 band parametric equalizers
Cascadable DSP effects that allow 10 band parametric
equalization
ALC/Compressor/Limiter on both DAC and ADC paths
The LM49350 employs advanced techniques to reduce pow-
er consumption, to reduce controller overhead, to speed de-
velopment time, and to eliminate click and pop. Boomer audio
power amplifiers were designed specifically to provide high
quality output power with a minimal amount of external com-
ponents. It is therefore ideally suited for mobile phone and
other low voltage applications where minimal power con-
sumption, PCB area and cost are primary requirements.
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Ultra low EMI, Class D loudspeaker amplifier with spread
spectrum control
Ground referenced output cap-less headphone amplifier
operation
Earpiece speaker amplifier with reduced power
consumption mode for mono differential line out
applications
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2.0 Applications
Stereo auxiliary inputs or mono differential input
Smart Phones
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Differential stereo microphone inputs with single-ended
option
Automatic level control for digital audio inputs, stereo
microphone inputs, and stereo auxiliary inputs
Mobile Phones and VOIP Phones
Portable GPS Navigator and Portable Gaming Devices
Portable DVD/CD/AAC/MP3/MP4 Players
Digital Cameras/Camcorders
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Flexible audio routing from input to output
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16 Step volume control for microphones with 2dB steps
32 Step volume control for auxiliary inputs in 1.5dB steps
Micro-power shutdown mode
3.0 Key Specifications
PHP at A_VDD = 3.3V, Stereo 32Ω, 1% THD 69mW/ch (typ)
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PLS at LS_VDD = 5V, 8Ω, 1% THD
PLS at LS_VDD = 4.2V, 8Ω, 1% THD
PLS at LS_VDD = 3.3V, 8Ω, 1% THD
PEP at A_VDD = 3.3V, 32Ω BTL, 1% THD
1.2W (typ)
825mW (typ)
495mW (typ)
58mW (typ)
Available in the 3.5 x 3.5 mm 36 bump micro SMD package
■ꢀSupply Voltage Range
ꢀꢀD_VDD = 1.7V to 2.0V
ꢀꢀLS_VDD and A_VDD = 2.7V to 5.5V
ꢀꢀI/O_VDD = 1.6V to 4.5V
Boomer® is a registered trademark of National Semiconductor Corporation.
© 2009 National Semiconductor Corporation
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