LG KF390 Service Manual page 29

3. TECHNICAL BRIEF
3.5.5 GSM PAM (U1001:TQM7M5012)
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.
C1063
68p
C1065
15p
LGE Internal Use Only
+VPWR
C1059
4.7u
L1008
6.8nH
L1009
1p
L1010
11
56p
L1011
12
3.9nH
10
[Fig. 1.7] GSM PAM Schematic
- 30 -
C1060 C1062
15p
1000p
2
BAND_SELECT
9
GSM_OUT
1
DCS_PCS_IN
DCS_PCS_OUT
8
GSM_IN
U1001
7 3
TQM7M5012
GND1 TX_EN
GND2
4
VBATT
6
NC1
5
NC2 VRAMP
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