LG KF690 Service Manual page 103

4. TROUBLE SHOOTING
4.16.3 Checking PAM Block
16
DCS_PCS_OUT U101
SKY77329
9
GSM_OUT
GSM_PA_BAND
Test Point Net name
TP1 GSM_PA_RAMP
TP2 GSM_PA_EN
TP3 +VPWR
LGE Internal Use Only
TP3
+VPWR
C134
C127
100p 22u
tcc_16085h_9_r
2
DCS_PCS_IN
7
GSM_IN
1
EFCH897MTDB1
TX_EN
3
BS
TP2
GSM_PA_EN
C141 C142
1000p 1000p
[Fig. 4.15] Schematic of PAM Block
[Fig. 4.15] Schematic of PAM Block
Description
Power Amp Gain Control. Typically, 0.2 ~1.6V
Power Amp Enable (ON : >2.5V, OFF : <0.7V)
PAM Supply Voltage (Vcc > 3V)
- 104 -
TP1
2.2K R105
GSM_PA_RAMP
C132
68p
R106
68
R107 R108
FL101
10 dB
91 91
3 2
R111
G2 G1
IN
1
O1 G3
51
4 5
R112 R113
8 dB
120 120
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Only for training and service purposes
DCS_PCS_TX
GSM_TX