Audio - LG GW520 Service Manual

3.13 Audio

3.13.1 Audio amplifier
GW520 use external audio AMP(MAX9877) for headphone.
The MAX9877 combines a high-efficiency Class D audio power amplifier with a stereo Class AB
capacitorless DirectDrive™ headphone amplifier. Maxim's 3
with active emissions limiting technology provides Class AB performance with Class D efficiency.
The MAX9877 delivers up to 725mW from a 3.7V supply into an 8Ω load with 87% efficiency to
extend battery life.
RADIO_OUT_R
RADIO_OUT_L
EAR_SPK_P
EAR_SPK_N
C317 C318
39p 39p
I2C1_SDA
I2C1_SCL
3.13.2 Microphone circuit
MIC300 is used both as a main and as a video .
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
VBAT
FB300
120
C300 C301
1u
C302 1u
A4
C1N
C304 1u A5
C1P
U300
C307 1u D1
INA2
C308 1u D2
INA1
C312 1u C1
MAX9877AEWP_TG45
INB2
C313 1u C2
EUSY0360201
INB1 OUT+
B2
BIAS
B3
SDA
C3
SCL
TP302 D4
RXIN+
TP303
B4
RXIN-
C325
1u
[Figure 3.13.1-1] Audio CODEC circuit diagram
VMIC_P
L304 100nH
C346
MIC_P
0.1u
L305 100nH
C347
MIC_N
0.1u
27p C350
27p
C349
VMIC_GND
[Figure 3.13.2-1] Microphone circuit diagram
3. BB Circuit Technical brief
GW520 service manual
GW520 service manual
GW520 service manual
rd
generation, filterless Class D amplifier
4.7u
A1
HSO_R
HPR
HSO_L
A2
HPL
C309 C310
39p 39p
R303
D5
R307
B5
OUT-
C322 C323
39p 39p
C345
MIC300
DNI
SPU0410HR5H-PB
SUMY0010609
4 O
3 G2
2 G1
1 P
C351 C352
100p 10u
- 49 -
CN300
0 1
0 2
(SUSY0024804)
LGE Internal Use Only