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LGE Internal Use Only
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3.4 LO generation and distribution circuits
The integrated LO generation and distribution circuits are driven by internal VCOs to support various
modes to yield highly flexible quadrature LO outputs that drive all GSM and UMTS band upconverters
and downconverters; with the help of these LO generation and distribution circuits, zero-IF architecture
is employed in all GSM and UMTS band receivers and transmitters to translate the signal directly from
RF to baseband and from baseband to RF.
Two fully functional fractional-N synthesizers, including VCOs and loop filters, are integrated within the
RTR6275 IC. The first synthesizer (PLL1) creates the transceiver LOs that support the UMTS
2100/1900/1800 transmitter, and all four GSM band receivers and transmitters including: GSM 850,
GSM 900, GSM 1800, and GSM 1900. The second synthesizer (PLL2) provides the LO for the UMTS
2100/1900/1800 receiver. An external TCXO input signal is required to provide the synthesizer
frequency reference to which the PLL is phase and frequency locked. The RTR6275 IC integrates
most of PLL loop filter components on-chip except two off-chip loop filter series capacitors, and
significantly reduces off-chip component requirement. With the integrated fractional-N PLL
synthesizers, the RTR6275 has the advantages of more flexible loop bandwidth control, fast lock time,
and low-integrated phase error
3.5 Off-chip RF Components
3.5.1 WCDMA PAM (U104: AWT6277R)
The UMTS PA output power is monitored by l power detector circuits(U101 : RTR6275) .
This detector voltage can be used for transmitter calibration and monitor to meet RF system
3. TECHNICAL BRIEF
- 25 -
[Figure 1.5] WCDMA PAM, Duplexer, Coupler
WCDMA
7dB
NEAR TO PAM
20dB
NEAR TO PAM
NEAR TO PAM
C154
3.9p
R122
47
C155
10p
2
45
31
TR100
KRX102U
100p
C158
3
GND1
6
GND2
GND3
7
GND4
9
11
GND5
RFIN
2
8
RFOUT
1
VCC1
VCC2
10
VMODE
4
5
VREF
U104
AWT6277R
FL101
G1
2
G2
3
G3
5
IN
1
O1
4
4
50OHM
COUP
3
IN
2
OUT
1
EFCH1950TDF1
CP0402A1950DNTR
U103
C151
1u
L123
1.8nH
L126
12nH
L121
5.6nH
3
ANT
4
PGND
RX
1
2
TX
ACMD-7602
FL102
R123
130
C157
NA
L122
NA
4.7u
C149
C148
8.2p
C162
100p
130
R124
2 2nH
L131
L127
R121
15nH
51
1u
C152
+VPWR
PA_R0
+VPWR
PA_ON
VREG_TCXO_2.85V
PWR_DET
Содержание Vodafone KU380
Страница 1: ...Date December 2007 Issue 1 0 Service Manual KU380 Service Manual Model KU380 Internal Use Only ...
Страница 151: ... 152 LGE Internal Use Only Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes ...
Страница 157: ... 158 LGE Internal Use Only Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes ...
Страница 188: ...Note ...
Страница 189: ...Note ...