- 33 -
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
3. TECHNICAL BRIEF
The SKY77329 Power Amplifier Module (PAM) is designed in a compact form factor for quad-band
cellular handsets comprising GSM850/900, DCS1800, PCS1900, and supports Class 12 General Packet
Radio Service (GPRS) multi-slot operation.
The module consists of a GSM850/900 PA block and a DCS1800/PCS1900 PA block, impedance
matching circuitry for 50
Ω
input and output impedances, and a Power Amplifier Control (PAC) block. A
custom CMOS integrated circuit provides the internal PAC function and interface circuitry. Two separate
Hetero-junction Bipolar Transistor (HBT) PA blocks are fabricated onto InGaP/GaAs die; one supports the
GSM850/900 bands, the other supports the DCS1800 and PCS1900 bands. Both PA blocks share
common power supply pins to distribute current. The GaAs die, the silicon die, and the passive
components are mounted on a multi-layer laminate substrate and the entire assembly is encapsulated
with plastic overmold.
3.5.6. GSM PAM (U101:SKY77329)
7.75dB
110
R120
C140
DNI
15nH
L116
C126
10p
C128
33u
19
PGND4
20
21
PGND5
PGND6
22
PGND7
23
24
PGND8
25
PGND9
4
RSVD1
8
RSVD2
12
RSVD3
TX_EN
1
6
V
APC
VBA
T
T
5
GND5
7
GSM_IN
9
GSM_OUT
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
SKY77329
U101
BS
3
DCS_PCS_IN
2
16
DCS_PCS_OUT
GND1
10
GND2
11
13
GND3
GND4
14
15
2
G1
3
G2
5
G3
1
IN
4
O1
EFCH897MTDB1
FL101
R114
82
33p
C130
10nH
L118
R119
110
C120
100p
R118
51
R115
82
NA
L114
C133
100p
82
R116
R112
2.2K
2.2nH
L117
C127
68p
GSM_PA_BAND
GSM_PA_EN
+VPWR
GSM_PA_RAMP
DCS_PCS_TX
GSM_TX
Figure 3. 5.6 GSM PAM Schematic