LGE Internal Use Only
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
- 76 -
4.5.2 Checking PAM Block
TP1. GSM_PA_RAMP : Power Amp Gain Control. typically, 0.5V < Vapc < 1.6V,
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 3.5V
Schematic of GSM PAM Block
TP1
TP2
TP4
TP3
11.4dB
82
R119
82
R120
R121
82
C35
100u
NA
C44
100p
C28
L122
4.7nH
PGND6
22
PGND7
23
24
PGND8
25
PGND9
4
RSVD1
8
RSVD2
12
RSVD3
TX_EN
1
6
VAPC
VBATT
5
17
PGND1
PGND10
26
PGND11
27
PGND12
28
29
PGND13
30
PGND14
PGND15
31
32
PGND16
33
PGND17
PGND18
34
PGND19
35
18
PGND2
36
PGND20
PGND3
19
PGND4
20
21
PGND5
SKY77329
U103
BS
3
DCS_PCS_IN
2
16
DCS_PCS_OUT
GND1
10
GND2
11
13
GND3
GND4
14
15
GND5
7
GSM_IN
9
GSM_OUT
C32
0.5p
33p
C34
33p
C30
C821
1p
C45
NA
68p
C29
R117
2.2K
100p
C819
GSM_PA_EN
GSM_PA_BAND
+VPWR
GSM_PA_RAMP
DCS_PCS_TX
TP3
TP4
TP2
TP1
Содержание CU575
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