LG KU950 - Checking Pam Block

4. TROUBLE SHOOTING
- 102 -
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
Test Point (RF Tx Level)
Schematic of PAM block
2012
Near to G-PAM
18nH
C148
C121
0.01u33u
C117
33p
R121
C123
0.01u
C116 33p
R107 100ohm
+VPWR
0.01u
C122
33pC118
33p
R113
5.6nH
C135
100ohmR105
R108 0
33p
C124
GSM_OUT
PGND
21
RSVD_GND
19
20
VAPC
VBATT
17
VCC1A
2
VCC1B
6
1
BS
DCS_PCS_IN
3
DCS_PCS_OUT
15
18
ENABLE
5
GND1
7
GND2 GND3
8
GND4
9
GND5
10 12
GND6 GND7
13
GND8
14 16
GND9
4
GSM_IN
11
U101
SKY77328
GSM_PA_BAND
GSM_PA_EN
GSM_PA_RAMP
TP4
TP3
TP2
TP1