LM49350 Datasheet, PDF (1/104 Pages) National Semiconductor (TI) – High Performance Audio Codec Sub-System with a Ground-Referenced Stereo Headphone Amplifier

LM49350
May 29, 2009
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
1.0 General Description
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.
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
69mW_RMS (typ) to a 32Ω single-ended stereo load with less
than 1% distortion (THD+N) when A_V_DD = 3.3V. The ear-
piece speaker amplifier delivers 58mW_RMS (typ) to a 32Ω
bridged-tied load with less than 1% distortion (THD+N) when
A_V_DD = 3.3V. The loudspeaker amplifier delivers up to
495mW into an 8Ω load with less than 1% distortion when
LS_V_DD = 3.3V and up to 1.2W when LS_V_DD = 5.0V.
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.
2.0 Applications
■ ^{Smart Phones}
■ ^{Mobile Phones and VOIP Phones}
■ ^{Portable GPS Navigator and Portable Gaming Devices}
■ ^{Portable DVD/CD/AAC/MP3/MP4 Players}
■ ^{Digital Cameras/Camcorders}
3.0 Key Specifications
■ ^P_HP ^{at A_V}_DD ^{= 3.3V, Stereo 32Ω, 1% THD 69mW/ch (typ)}
■ ^P_LS ^{at LS_V}_DD ^{= 5V, 8Ω, 1% THD}
1.2W (typ)
■ ^P_LS ^{at LS_V}_DD ^{= 4.2V, 8Ω, 1% THD}
825mW (typ)
■ ^P_LS ^{at LS_V}_DD ^{= 3.3V, 8Ω, 1% THD}
495mW (typ)
■ ^P_EP ^{at A_V}_DD ^{= 3.3V, 32Ω BTL, 1% THD 58mW (typ)}
■ ^{SNR (Stereo DAC at 48kHz)}
■ ^{SNR (Stereo ADC at 48kHz)}
■ ^{Shutdown Current}
■ ^{PSRR at 217 Hz, A_V}_DD ^{= 3.3V, (HP from}
AUX)
96dB (typ)
94dB (typ)
2.3µA (typ)
97dB (typ)
4.0 Features
■ ^{High performance 96dB SNR stereo DAC}
■ ^{High performance 94dB SNR stereo ADC}
■ ^{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}
■ ^{Dual 5 band parametric equalizers}
■ ^{Cascadable DSP effects that allow 10 band parametric}
equalization
■ ^{ALC/Compressor/Limiter on both DAC and ADC paths}
■ ^{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
■ ^{Stereo auxiliary inputs or mono differential input}
■ ^{Differential stereo microphone inputs with single-ended}
option
■ ^{Automatic level control for digital audio inputs, stereo}
microphone inputs, and stereo auxiliary inputs
■ ^{Flexible audio routing from input to output}
■ ^{16 Step volume control for microphones with 2dB steps}
■ ^{32 Step volume control for auxiliary inputs in 1.5dB steps}
■ ^{Micro-power shutdown mode}
■ ^{Available in the 3.5 x 3.5 mm 36 bump micro SMD package}
■ Supply Voltage Range
  D_V_DD = 1.7V to 2.0V
  LS_V_DD and A_V_DD = 2.7V to 5.5V
  I/O_V_DD = 1.6V to 4.5V
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© 2009 National Semiconductor Corporation 201941
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