Rf Subsystem Of Pmb8815 (U01) - LG -T510 Service Manual

3.5 RF Subsystem of PMB8815 (U201)
R XT XEN
D igR F
R XT XD A
R ESET_N
C T R LEN
3-W ire
C T R LD A
C T R LC LK
F E4
F SYS12_EN
SYSC LK_EN
SYSC LK_BBPLL
F SYS1
F SYS2
26 M H z XO
XOX
3.5.1 GENERAL DESCRIPTION
The PMB8815 RF subsystem is designed for dual-band GSM voice and data applications (GPRS class 12). The
system can be configured to support one low band, GSM850 or EGSM900, and one high band, DCS1800 or
PCS1900. A block diagram of the RF subsystem is given in Figure 3-4-1.
LGE Internal Use Only
D C OC
D C OC
C ontrol/
Bus Sequencing
C H AN
Sigm a -D elta M ASH
M odulator
M ulti M odulus
D ivider
T D C L(z )
LD O
D 2 B
2.5V
Figure. 3-5-1 Block DIAGRAM of RF Subsystem
AD C
AD C
Gauss F ilter
M OD
Integrated
3.8GH z D C O
R F S u b system
L DO L D O L D O
TR X M M D TD C
1.4V 1.3V 1.3V
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3. TECHNICAL BRIEF
LPF
LPF
:2/
:4
PABIAS
D AC
R am p
D AC
AD C
:4
:2
SER
L D O L D O
PAR
M S XO
1.3V 1.3V
Only for training and service purposes
R X12/R X12X
850/900M H z
R X34/R X34X
1800/1900M H z
PABIAS /
F E3
VR AM P
VD ET
T X1
850/900M H z
T X2
1800/1900M H z
PAEN
PABS
F E1
F E2