LG KM710 Service Manual page 44

4.1.2.3 FEM
Pass wanted signal and include LNA matching circuit.
U401
PCS DCS
FL400
4.1.2.4 RF Transceiver (B6PLD)
Digital Interface to Baseband. Integrate LNA and VCO circuit.
X400
U401
U403
FL400
SW400
4.1.2.5 DCXO
Produce RF and BB reference Clock - 26MHz Clock.
R401
C408
X400
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EGSM
/GSM
22p
U400
U402
3p
C412
3p
C414
C416 3.3p
C418 3.3p
L405
L406
18nH
L407
120
R403
5
1
120
R407
FL400
ESHS-C090SR
GND5 GSM18001900_TX
16 11
GND4 GSM900_TX
15 13
GND3
14 4.7nH
GND2 GSM1900_RX2
9 6
GND1 GSM1900_RX1
7 5
GSM1800_RX2
4
GSM1800_RX1
3
VC2 GSM900_RX2
10 2
VC1 GSM900_RX1
12 1
3.9nH
<Fig.3> SAW Filter Bark Circuit Diagram
C_VCCRF VCC_SYN
C400
0.01u
C403
0.01u
C404
3.9p
C406
3.9p
C405
33nF
C409 C407
22p 0.1u
A1
PCSLNAI
B1
PCSLNAIB GNDVCXO_OR
C2
PCSDCSGND VOUTEF2
C1
DCSLNAI VCCVCXO
D1
DCSLNAIB VOUTEF1
D2
DCSG90GND VCCLOGIC2
E1
U401
G90LNAI GNDLOGIC
F1
G90LNAIB CLOGIC1
E2
R2A60167BG
G90G85GND VCCLOGIC1
G1
G85LNAI STROBE
H1
G85LNAIB SYSCLK
F2
G85GND RXTXDATA
G2
GNDLNA_TX1 RXTXEN
H2
TXON
E3
GNDDMIXIN CTRLEN
J2
DMIXIN CTRLDATA
J1
DMIXINB CTRLCLK
100ohm
R404
R406
C425
68
22p
100ohm
C423 0.01u
R408
R409
100ohm
<Fig.4> RF Transceiver Circuit Diagram
GNDVCXO_OR
VOUTEF2
<Fig.5> DCXO Circuit Diagram
- 45 -
4. Trouble Shooting
3p
C412
L402
3p
C414
A1
B1
C2
C1
C416 3.3p
D1
L404
D2
3.3p
C418 E1
F1
E2
G1
4.7nH L405
H1
L406
F2
18nH
4.7nH L407
G2
H2
E3
J2
J1
BT_CLK
C408
68p
X400
FA-23H
R401
U400
47K
1 VCC
L403
_OE
5
2
26MHz
A
4
8.2nH 3
Y
GND
SN74LVC1G125DRLR
B9
XON
C8
D7
0.1u
C9 C417
D8
SLICER_IN
D9
VCC_SYN
E7
0.01u C420 0.01u
C419
F7
E9
VRIO
E8
F8
F9
DIGITALRF_DATA
G7
DIGITALRF_ENABLE
G6
TEST1
G9
DIGITALRF_RF_CS
G8
DIGITALRF_RF_DATA
H9
DIGITALRF_RF_CLK
SYSCLKEN
C_VCCRF
C408
68p
X400
FA-23H
R401
47K
26MHz
B9
XON
C8
D7
LGE Internal Use Only
PCSLNAI
PCSLNAIB
PCSDCSGND
DCSLNAI
DCSLNAIB
DCSG90GND
G90LNAI
G90LNAIB
G90G85GND
G85LNAI
G85LNAIB
G85GND
GNDLNA_TX1
TXON
GNDDMIXIN
DMIXIN
DMIXINB
VRIO
C410
0.01u
R402
SYSCLK
1K