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3. TECHNICAL BRIEF
3.15.1 Audio amplifier
We use MAX9877 Audio AMP, which have speaker & headphone amplifiers. An audio signal path can
be selected by I2C command.
3.15.2 Microphone circuit
LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Figure 17. Audio AMP Circuit Diagram
AUDIO AMP SUB SYSTEM & SIGNAL DISTRIBUTOR
C302
1u
C312 1u
0R313
OUT+
B5
OUT-
C4
PGND
C5
PVDD
RXIN+
D4
B4
RXIN-
SCL
C3
SDA
B3
B1
VDD
A3
VSS
B2
BIAS
C1N
A4
C1P
A5
D3
GND
HPL
A2
HPR
A1
INA1
D2
INA2
D1
C2
INB1
C1
INB2
D5
C309
MAX9877AEWP_TG45
U303
1u
C305 1u
C308 1u
VBAT
0R314
C304 1u
C301
1u
1u
C315
0R300
C311 1u
HSO_L
HSO_R
BB_SND_L
BB_SND_R
I2C_SCL
SPK_N
SPK_P
i2C_SDA
FM_SND_R
FM_SND_L
Figure 18. Microphone Circuit Diagram
MICMIC
10u
C322
39p
C321
C317
39p
L302
100nH
MICBIAS
EVLC14S02050
VA300
L304
100nH
C320
22n
100nH
L303
22n
C319
39p
C318
MIC300
SPU0409HE5H-PB
2
G1
G2
3
O
4
P
1
MIC_P
MIC_N