3. TECHNICAL BRIEF
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LGE Internal Use Only
Copyright © 011 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3.5 RF Subsystem of PMB8815 (U201)
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.
Figure. 3-5-1 Block DIAGRAM of RF Subsystem
Multi Modulus
D ivider
T DC
L(z )
:2/
:4
SER
RF Subsystem
Integrated
3.8GHz DCO
26 MH z
TX1
850/900MH z
TX2
1800/1900MHz
C TR LEN
C TR LDA
CT RLCLK
SYSCLK_EN
F SYS1
F SYS2
VR AMP
VD ET
XOX
XO
tr
aP
B
B/
U
MP
Ramp
D AC
DigR F
3-Wire
Bus
ADC
:4
:2
R XT XEN
R XT XDA
PAEN
PABS
F E1
F E2
PAR
D
M
M
D
DV
C
DT
D
DV
1.3V
LPF
LPF
RX12/RX12X
850/900MH z
RX34/RX34X
1800/1900MHz
DCOC
DCOC
ADC
ADC
S
M
D
DV
OX
D
DV
PABIAS /
FE3
PABIAS
D AC
LDO
M M D
LDO
TDC
1.3V
1.3V
1.3V
1.4V
X
RT
D
DV
C H AN
M OD
Sigma -Delta MASH
Modulator
Gauss Filter
Control/
Sequencing
F E4
SYSC LK_BBPLL
R ESET_N
F SYS12_EN
LDO
XO
LDO
M S
LDO
TRX
TA
BV
V5
.5
-V
50
.3
2F
R
D
DV
LD O
D 2 B
2.5V
1F
RV
V8
.1