LGE Internal Use Only
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
- 89 -
4.6.4 Checking PAM Block
PAM Control Signal
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
TP4
TP1
TP2
TP3
(1%)
5
G2
1
IN
4
O2
B7844
FL103
C1052
100u
0.5p
C1828
220
R1020
33p
C1046
R1018
270
R1021
220
68p
C1038
100p
C1511
L172
4.7nH
R1008
2.2K
R1016
15
12
GND6
GND7
13
14
GND8
OUT_DCSPCS
5
OUT_GSM
1
SW1
9
SW2
11
VB
3
10
VC
X101
MQW5V0C869M
2
GND1
4
GND2
6
GND3
GND4
7
8
GND5
R1014
15
270
R1019
C1056
51p
R1022
51
C1051
33p
TX_EN
VBATT
4
VCC21
8
VCC22
18
13
VCC_OUT
VRAMP
6
5
VREG
+VPWR
BS
2
1
DCS_PCS_IN
DCS_PCS_OUT
16
9
GND1
11
GND2
GND3
12
GND4
14
15
GND5
GND6
17
GSM_IN
7
GSM_OUT
10
19
PGND1
PGND2
20
21
PGND3
3
U102
AND0041
0.5p
C1829
6.8nH
L402
C1041
22n
G2
1
IN
2
OUT
FL104
NFM21PC105B1A3
G1
3
4
GSM_PA_BAND
GSM_PA_EN
GSM_PA_RAMP
Schematic of PAM block
TP1
TP4
TP2
TP3
Summary of Contents for TU550
Page 1: ...Date May 2007 Issue 1 0 Service Manual Model TU550 Service Manual TU550 Internal Use Only ...
Page 185: ...Note ...
Page 186: ...Note ...