3. TECHNICAL BRIEF
3.13.1. Audio amplifier sub system IC with 3D effect
Audio amplifier sub system IC is an audio power amplifier capable of delivering 500mW of
continuous average power into a mono 8Ω load, 25mW per channel of continuous average power
into stereo 32Ω single-ended (SE) loads. The LM4845 features a 32-step digital volume control and
eight distinct output modes. The digital volume control, 3D enhancement, and output modes
(mono/SE/OCL) are programmed through a two-wire I2C interface that allows flexibility in routing
and mixing audio channels.
AMP_IN_R
AMP_IN_L
SDA
SCL
2V72_IO
C239
220n
R436
0
C245
220n
R437
0
R229
100K
C247
0.1u
Figure 22 Audio amplifier Sub-system IC
3V3_AUDIO
SPK_N
SPK_RCV_N
SPK_RCV_SEL
RCV_N
C242
C240
C244
100p
100p
0.1u
3V3_AUDIO
FM_SND_R
AMP_IN_R
FM_BBP_SEL
BBP_SND_R
C251
0.1u
Figure 23 Audio signal distribute analog switch
3V3_AUDIO
C238
C236
C237
0.1u
1u
4.7u
B4
D1
PHONE_IN
MONO+
D4
B1
RIN
MONO-
E4
D5
LIN
U210
ROUT
LM4845
B5
NC1
A2
D2
I2CSPIVDD
NC2
A1
E5
SDA
LOUT
B2
SCL
B3
ID_ENB
E1
E2
I2CSPI_SEL
CBYPASS
C248
470n
U208
NLAS5223BMNR2G
1
10
SPK_P
VCC
NO2
2
9
SPK_RCV_P
NO1
COM2
3
8
COM1
IN2
4
7
RCV_P
IN1
NC2
5
6
NC1
GND
C243
C241
100p
100p
U211 NLAS5223BMNR2G
1
10
FM_SND_L
VCC
NO2
2
9
AMP_IN_L
NO1
COM2
3
8
COM1
IN2
4
7
BBP_SND_L
IN1
NC2
5
6
NC1
GND
- 50 -
SPK_P
SPK_N
HS_OUT_R
HS_OUT_L
C447
0.22u