LG FM300 Service Manual page 15

3.1.4 20 MHz Clock (Crystal, X400)
For the generation of the reference frequency for BCM5358U an external Crystal unit is used.
The XTAL ground is separated from main ground for reducing noise. It is used for the various clocks,
including the clock for the 10/100 MAC core (25 MHz) and the MIPS32 74K, UART, and USB 2.0 host in
BCM5358U.
LGE Internal Use Only
20MHz CRYSTAL
X400
CXC3X200000GHVRG00
4
GND2 HOT2
1
HOT1 GND1
20MHz
C422
EXXY0027801
33p
FB401 FB400
600 600
GND
Figure 3.4 Crystal Circuit diagram
R406 0
R407
3
220
2
C423
33p
XTAL_GND
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3. TECHNICAL BRIEF
3. TECHNICAL BRIEF
XTAL_IN
XTAL_OUT
Only for training and service purposes