Datasheet

AUX_OUT
EP_OUT
LS_OUT
BYPASS
HP_VMIDFB
HP_VMID
HPL_OUT
HPR_OUT
VREF_FLT
INT_BIAS
EXT_BIAS
MIC_DET
EXT_MIC
INT_MIC
CP_OUT
CP_IN
PLL_FLT
MCLK
SCL/SCK
SDA/SDI
TEST_MODE/CS
SPI_MODE
I2S_CLK
I2S_WS
I2S_SDI
I2S_SDO
PCM_CLK
PCM_SYNC
PCM_SDI
IRQ
AUX_R
AUX_L
POWER
MANAGEMENT
and CONTROL
CLOCKS and
6'_PLL
REGISTERS
I
2
C/SPI
SLAVE
AB
AB
AMP
BIAS
and DET
MIC
BIAS
and DET
BG
AB
AB
AB
AUTOMATIC GAIN
CONTROL
6'
MONO
ADC
6'
STEREO
DAC
DIGITAL AUDIO INTERFACE with PCM
-
I
2
S BRIDGE
LEVEL SHIFTERS
G
7
.
11
RIGHT
LEFT
CPI
-34.5 dB to 12 dB
MIC
SIDETONE
-46.5 dB to
12 dB
0 dB to
-30 dB
6 dB to
36 dB
D
PCM_SDO
GPIO2
L
R
GPIO1
FIR FILTER
and
DIGITAL 3D
ALGORITHM
A_V
DD
D_V
DD
LS_V
DD
LS_V
SS
A_V
SS
D_V
SS
BB_V
DD
PLL_V
DD
LM49370
SNAS356D –FEBRUARY 2007–REVISED MARCH 2012 www.ti.com
DESCRIPTION
The LM49370 is an integrated audio subsystem that supports both analog and digital audio functions. The
LM49370 includes a high quality stereo DAC, a mono ADC, a stereo headphone amplifier, which supports output
cap-less (OCL) or AC-coupled (SE) modes of operation, a mono earpiece amplifier, and an ultra-low EMI spread
spectrum Class D loudspeaker amplifier. It is designed for demanding applications in mobile phones and other
portable devices.
The LM49370 features a bi-directional I
2
S interface and a bi-directional PCM interface for full range audio on
either interface. The LM49370 utilizes an I
2
C or SPI compatible interface for control. The stereo DAC path
features an SNR of 85 dB with an 18-bit 48 kHz input. In SE mode the headphone amplifier delivers at least 33
mW
RMS
to a 32Ω single-ended stereo load with less than 1% distortion (THD+N) when A_V
DD
= 3.3V. The mono
earpiece amplifier delivers at least 115mW
RMS
to a 32Ω bridged-tied load with less than 1% distortion (THD+N)
when A_V
DD
= 3.3V. The mono speaker amplifier delivers up to 490mW 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 LM49370 employs advanced techniques to reduce power consumption, to reduce controller overhead, to
speed development 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 components. It is therefore
ideally suited for mobile phone and other low voltage applications where minimal power consumption, PCB area
and cost are primary requirements.
LM49370 Overview
Figure 1. Conceptual Schematic
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Product Folder Links: LM49370