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LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3.5.5 GSM PAM (U102 : SKY77329)
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.
[Fig. 3.7] GSM PAM Schematic
2.2K
R107
68
R108
C141
NA
C137
NA
R114
120
56p
C136
15p
C140
C132
68p
G1
2
G2
3
G3
5
IN
1
O1
4
FL102
EFCH897MTDB1
R112
120
51
R115
33u
C127
C126
1u
+VPWR
C139
15p
56p
C138
22
PGND7
23
24
PGND8
25
PGND9
4
RSVD1
8
RSVD2
12
RSVD3
TX_EN
1
6
VAPC
VBATT
5
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
PGND6
SKY77329
U102
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
17
R110
91
R109
91
GSM_TX
GSM_PA_EN
GSM_PA_BAND
GSM_PA_RAMP
DCS_PCS_TX
Z3X-BOX.COM
Summary of Contents for HB620
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