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September 23, 2008
LM49350
High Performance Audio Codec Sub-System with a
Ground-Referenced Stereo Headphone Amplifier & an
Ultra Low EMI Class D Loudspeaker Amplifier with Dual
I
2
S/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 I
2
S or PCM audio
interfaces for full range audio and an I
2
C 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)
■ 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
■
SNR (Stereo DAC at 48kHz) 96dB (typ)
■
SNR (Stereo ADC at 48kHz) 94dB (typ)
■
Shutdown Current 2.3µA (typ)
■
PSRR at 217 Hz, A_V
DD
= 3.3V, (HP from
AUX)
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 I
2
S or PCM compatible audio interfaces
■
Read/write I
2
C 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
Boomer® is a registered trademark of National Semiconductor Corporation.
© 2008 National Semiconductor Corporation 201941 www.national.com
LM49350 High Performance Audio Codec Sub-System with a Ground-Referenced Stereo
Headphone Amplifier & an Ultra Low EMI Class D Loudspeaker Amplifier with Dual I
2
S/PCM
Digital Audio Interfaces
Verzeichnis
- ・ Konfiguration des Pinbelegungsdiagramms on Seite 11
- ・ Abmessungen des Paketumrisses on Seite 102
- ・ Teilenummerierungssystem on Seite 10
- ・ Markierungsinformationen on Seite 10
- ・ Blockdiagramm on Seite 2 Seite 97
- ・ Typisches Anwendungsschaltbild on Seite 3
- ・ Beschreibung der Funktionen on Seite 1
- ・ Technische Daten on Seite 1 Seite 12 Seite 15
- ・ Anwendungsbereich on Seite 1 Seite 12
- ・ Elektrische Spezifikation on Seite 12 Seite 15 Seite 17
