Multi Port Switch - LG KE820 Service Manual

3.13.2. Microphone with gain switching circuit
As controlling the MIC_GAIN_SEL, Microphone sensitivity can be selected both -42dB
(MIC_GAIN_SEL set low) and -30dB(MIC_GAIN_SEL set high)
MIC1_P
MIC1_N
VMICP
VMICN
C125
27p

3.14. Multi port switch

Multi port switch has employed to decrease MMI(Multi Media Interface) connector's pin number. USB,
USART, Remote controlled Headset is connected via this multi port switch. When USB VBUS voltage
is detected Multi port 0 and 1 is connected to USB_DP and USB_DM each. If the remote controlled
headset is plugged into MMI connector, then multi port 0 and 1 in go through REMOTE_INT and
REMOTE_ADC.
Table 8 Multi port switch truth table
VBUS_USB='L'
JACK_DETECT='L'
Pin6 REMOTE_INT
Pin7 REMOTE_ADC
L104
C114
0.1u
100nH
C115
100p
L105
C116
0.1u
100nH
R120 0
R122 0
C126 C127 C128
27p 10u 100p
Figure 24 Microphone with Gain switching circuit
VBUS_USB='L'
JACK_DETECT='H'
TXD
RXD
3. TECHNICAL BRIEF
C117
VA100 VA101
100p
- 51 -
MIC100
1
OUT
2
G1
3
G2
4
PWR
5
G3
SP0102BE3
VA102
VBUS_USB='H'
USB_DP
USB_DM