Dcxo; Front End Module Control; Only For Training And Service Purposes - LG KS360 Service Manual

3. TECHNICAL BRIEF

3.24 DCXO

The transceiver contains a fully integrated 26MHz digitally controlled crystal oscillator (DCXO) with
three outputs for the system clock, one output for the GSM baseband and two additional for other
subsystems (GPS, Bluetooth, etc.). The only external part of the oscillator is the crystal itself. The
overall pulling range of the DCXO consists of eight subranges. The subrange closest to the '0ppm' at
the middle AFC-value is selected during the calibration process in the mobile's production and is used
for the rest of the lifetime. The frequency tuning is performed along the selected subrange by
programming the frequency control word (XO_TUNE) via the three wire bus ("3Wbus").

3.25 Front End Module control

Implemented in the Transceiver are two outputs for direct control of front end modules with two logic
input pins to select RX- and TX-mode as well as low- and high band operation.
PAD600
PAD601
PAD602
GSM850_EGSM TX
DCS_PCS TX
LGE Internal Use Only
CN600
MM8430-2600RB3
R608 C631
0 5p
C633
L605
0.75p
12nH
VC1 VC2
PIN 14 PIN 13
H L
L H
GSM850 RX L
L
EGSM900 RX L L
DCS1800 RX L L
PCS1900 RX L L
Figure 27. FEM Circuit Diagram
RF
C622
33p
C627
33p
C632
22p
ANT
17
L604
NA
C643 C644 C645
C646 C647
2.5p 2.5p
3.9p
3.9p 3.3p
L609
L608
L607
18nH 5.1nH
22nH
GSM900
GSM850 DCS1800
Copyright © 2008 LG Electronics. Inc. All right reserved.
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VC1
VC2
U601
LMSP43NA-782
C634
0.5p
C641
DNI
C648 C649 C650
3.3p 5.6p 5.6p
L610
5.6nH
PCS1900

Only for training and service purposes