LG KE600 - Cell Phone Service Manual page 105

5. Trouble shooting
5.15.4 Checking PLL Control signals
Checking Points
Figure 7. Transceiver
RF Transceiver Circuit Diagram
85_RF
C623
0.1u
FE2
33
VBIAS
34
VDDTX1V5 VDDRX2V8
35
TX1 VDDRX1V5
U602
36
TX2 VCO_RC
PMB6272
37
VDDTX2V8 VDDVCO2V8
R617 10 38
VDDMIX2V8 EN
39
GND3 VDDXO2V8
40
FSYS1
GND4 GND1
41
C630 C631
0.1u 0.1u
C633
Figure 8. Transceiver Circuit
1V5_RF
2V85_RF 2V7_VCXO
R615
0
C624 C626 C627
C625
C628
47n
0.1u 0.1u 0.1u
0.1u
20
19 R616 820
18
17
16
15 C629
14
13
2V7_VCXO
26MHz
VCC GND
4 2
C641 C632
NA OUT VCONT
1u
3 1
X601
100p R620 0
Checking Flow
Waveform
1000p
Figure 9. PLL Control Waveform
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