Checking Pam Block - LG U310 Service Manual

4. TROUBLE SHOOTING

4.6.4 Checking PAM Block

PAM Control Signal
TP1. GSM_PA_RAMP : Power Amp Gain Control. typically, 0.5V < Vapc < 2.6V,
TP2. GSM_PA_EN : Power Amp Enable
(Power ON : higher than 2.5V , Power OFF : lower than 0.7V)
TP3. GSM_PA_BAND : Power Amp Band Selection Control
(GSM Mode : lower than 0.7V , DCS/PCS Mode : higher than 2.5V)
TP4. +VPWR : PAM Supply Voltage Vcc higher than 3.28V
TP1
TP1
TP2
TP4
Test Point (RF Tx Level)
C1016 C1013
33u
0.01u
C1024
0.01u
C1027 C1023
22u
C1028 0.01u
68p
15 3
DCS_PCS_OUT DCS_PCS_IN
11 4
EGSM_OUT U1001 EGSM_IN
19 18
RSVD_GND ENABLE
SKY77318
21 1
P_GND BS
SMPY0014001
R1024
C1058
15p
Schematic of PAM block
- 92 -
+VPWR
TP4
TP2
R1017 100ohm
GSM_PA_EN
C1044
15p
100ohm
GSM_PA_BAND
TP3
TP3