Only For Training And Service Purposes - LG KF700 Service Manual

3.5.5 GSM PAM (U101: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, 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.
C134
56p
L502
1.5nH
L501
16
8.2nH
DCS_PCS_OUT
9
GSM_OUT
R600
0
C139
82p
L111
NA
Copyright © 2008 LG Electronics. Inc. All right reserved.

Only for training and service purposes

C135
C128
100p 22u
tcc_16085h_9_r
2
DCS_PCS_IN
7
U101 GSM_IN
SKY77329
1
TX_EN
3
BS
GSM_PA_BAND
C145
1000p
[Fig. 3.7] GSM PAM Schematic
- 27 -
3. TECHNICAL BRIEF
2.2K R106
GSM_PA_RAMP
+VPWR
C133
68p
R107
68
R108
FL101
10 dB
91
EFCH897MTDB1
3 2
R111
G2 G1
IN
1
O1 G3
51
4 5
R112
8 dB
120
GSM_PA_EN
C146
1000p
DCS_PCS_TX
R109
91
GSM_TX
R113
120
LGE Internal Use Only