3.10 Microphone. LG KG291, KG290

3. TECHNICAL BRIEF

3.10 Microphone

The microphone is placed to the Rear cover and contacted to main PCB. The audio signal is passed to

VINNORP and VINNORN pins of AD6721. The voltage supply VMIC is output from AD6721, and is a biased voltage for the VINNORP. The VINNORP and VINNORN signals are then A/D converted by the voiceband ADC part of AD6721.The digitized speech (PCM 8KHz ,16KHz) is then passed to the DSP section of AD6721 for processing (coding, interleaving etc).

MIC

L

H

MIC_PATH_SEL

AD6721

AIT813G

2V5_VMIC

R221

1K

R227

2.2K

MULTI_MIC_P

MIC_P

MIC_PATH_SEL

VINNORP

C219

39p

C215

10u

2V8_VMEM

1

U204

NLAS5223BMNR2G

10

VCC NO2

2

NO1 COM2

9

3

COM1

4

IN1

5

NC1

IN2

8

NC2

7

GND

6

C216

1u

C217

100K

MULTI_MIC_N

MIC_N

MIC_PATH_SEL

VINNORN

MIC_P

R231 100ohm

C222

39p

R232 100ohm C228 0.1u

MIC_N

C223

39p

OB4-15L42-C33L

2

1

MIC200

R234

2.2K

Figure 3-12. Connection between Microphone and AD6721

3.11 Main Speaker

ACCDETECT

JACKSENSE

AIN3L

AIN3R

AIN3COMMON

AOUT1P

AOUT1N

AOUT2P1

AOUT2P2

AOUT2N1

AOUT2N2

AOUT3L

AOUT3R

U16

M15

N14

M16

N17

N16

T14

R190

C152

U14

T15

U15

M17 R124

N15 R125

4.7

0.1u

4.7

4.7

R122

R123

JACK_DETECT

FM_AUDIO_L

FM_AUDIO_R

4.7

4.7

AUXOP_L

AUXOP_R

R120

R121

C156 C157

39p 39p

4.7

4.7

C153

NA

ABB_P

ABB_N

39p

C158 C159

39p 39p

REC_P

C155

39p

REC_N

Copyright © 2007 LG Electronics. Inc. All right reserved.

Only for training and service purposes

- 33 LGE Internal Use Only

3. TECHNICAL BRIEF

ABB_P

AMP_SHDN

C207

0.47u

R202 0

R209 10K

ABB_N

C208

0.47u

R211 10K

R213

100K

C200 NA

R201 39K

C209

220n

1

U201 TPA6205A1DRBR

_SHUTDOWN VDD

6

2

BYPASS VO-

8

3

IN+ VO+

5

4

INGND

PGND

7

9

C211 NA

R215 39K

ACOUSTIC & MIDI

VBAT VBAT

C203

2.2u

C204

0.1u

R208 0

R210 0

SPK_P

SPK_N

SPK_N

SPK_RCV_N

SPK_SEL

REC_N

C201

0.1u

C202

39p

R214

200K

1

U202

NLAS5223BMNR2G

VCC NO2

10

9 2

NO1

3

COM1

COM2

IN2

8

4

5

IN1

NC1

NC2

7

GND

6

L

H

SPK_SEL

RECEIVER

SPEAKER

SPK_P

SPK_RCV_P

SPK_SEL

REC_P

Figure 3-13. MAIN SPEAKER

LGE Internal Use Only - 34 Copyright © 2007 LG Electronics. Inc. All right reserved.

Only for training and service purposes