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4. TROUBLE SHOOTING
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4.7.4 Checking PAM Block
TP1. GSM_PA_RAMP : Power Amp Gain Control. typically, 0.2V < Vramp < 1.6V
TP2. GSM_PA_EN : Power Amp Enable
(Power ON : higher than 1.25V , Power OFF : lower than 0.4V)
TP3. GSM_PA_BAND : Power Amp Band Selection Control
(GSM Mode : -0.2V < VBS < 0.4V , DCS/PCS Mode : 1.25V < VBS < 3.0V)
TP4. +VPWR : PAM Supply Voltage Vcc higher than 3.0V
Schematic of GSM PAM Block
TP1
TP2
TP3
TP4
Rev.D
EGSM
C136
0.01u
10nH
L116
100p
C438
4
p 1.5nH
L403
100ohm
100ohmR113
R117
100ohm
R107
C153
15p
EFC
FL1
C123
0.01u
68p
C139
C134
0.01u
GND3
9
GND4
10
GND5
GND6
12
GND7
13
GND8
14
GND9
16
21
P_GND
19
RSVD_GND
VAPC
20
17
VBATT
2
VCC1A
6
VCC1B
BS
1
DCS_PCS_IN
315
DCS_PCS_OUT
EGSM_IN
4
EGSM_OUT
11
ENABLE
18
GND1
5
GND2
7
8
SKY77318
U101
C149
15p
C121
33u
C138
NA
+VPWR
GSM_PA_BAND
GSM_PA_EN
GSM_PA_RAMP
TP2
TP4
TP3
TP1