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3. TECHNICAL BRIEF
3.5 Off-chip RF Components
3.5.1 UMTS PAM (U104: RF5184)
The UMTS PA output power is monitored by power detector circuits (U101 : RTR6280) .
This detector voltage can be used for transmitter calibration and monitor to meet RF system
specification.
FL104
FL104
B7683
B7683
ANT
ANT
TX
TX
L121
L121
RX1
RX1
RX2
RX2
GND1
GND1
L122
L122
GND2
GND2
GND5
GND5
NA
NA
GND3
GND3
GND4
GND4
L125
L125
GND3
GND3
GND4
GND4
GND2
GND2
GND5
GND5
GND1
GND1
GND6
GND6
L131
L131
1nH
1nH
C194
C194
33p
33p
WCDMA_2100
WCDMA_2100
ANT
ANT
FL106
FL106
B7646
B7646
C1001
C1001
DNI
DNI
C1003
C1003
15p
15p
C1004
C1004
RX_WCDMA_2100
RX_WCDMA_2100
L133
L133
2.2nH
2.2nH
3.5.2 VCTCXO (X101 : DSA321SCE-19.2M)
The Voltage Controlled Temperature Compensated Crystal Oscillator (VCTCXO) provides the reference
frequency for all RFIC synthesizers as well as clock generation functions within the MSM6280 IC. The
oscillator frequency is controlled by the MSM6280 ICs. TRK_LO_ADJ pulse density modulated signal in
the same manner as the transmit gain control TX_AGC_ADJ. A two-pole RC low pass filter is
recommended on this control line.
The PM6658 IC controls the handset power-up sequence, including a special VCTCXO warm-up
interval before other circuits are turned on. This warm-up interval (as well as other TCXO controller
functions) is enabled by the MSM TCXO_EN line . The PM6658 IC VREG_TCXO regulated output
voltage is used to power the VCTCXO and is enabled before most other regulated outputs.
Any GSM mode power control circuits within the MSM6280 IC require a reference voltage for proper
operation and sufficient accuracy. Connecting the PM6658 IC REF_OUT directly to the MSM6280 IC
GSM_PA_PWR_CTL_REF provides this reference. This sensitive analog signal needs a 0.1 µF low
frequency filter near to MSM side, and isolate from digital logic and clock traces with ground on both
sides, plus ground above and below if routed on internal layers.
LGE Internal Use Only
U103
U103
LDC15836M20Q-360
LDC15836M20Q-360
L120
L120
2.7nH
2.7nH
C177
C177
56p
56p
1.5p
1.5p
RX_WCDMA_850_P
RX_WCDMA_850_P
C180
C180
C181
C181
1.2p
1.2p
DNI
DNI
L123
L123
12nH
12nH
1.5p
1.5p
RX_WCDMA_850_M
RX_WCDMA_850_M
R116
R116
PDET_IN
PDET_IN
82
82
PWR_DET
PWR_DET
U105
U105
LDC151G8820Q-359
LDC151G8820Q-359
L130
L130
2.2nH
2.2nH
C188
C188
5.6p
5.6p
TX
TX
RX
RX
C199
C199
C195
C195
DNI
DNI
1p
1p
33p
33p
PWR_DET
PWR_DET
[Fig. 3.5] UMTS PAM, Duplexer, Coupler
- 24 -
C178
C178
2200p
2200p
C186
C186
2200p
2200p
NC4
NC4
VCC1_CELL
VCC1_CELL
VREG_WCDMA_PA
VREG_WCDMA_PA
13
13
6
RFOUT_CELL
RFOUT_CELL
RFIN_CELL
RFIN_CELL
14
14
5
NC5
NC5
VMODE_CELL
VMODE_CELL
15
15
4
RFOUT_PCS
RFOUT_PCS
VREG_CELL
VREG_CELL
16
16
3
NC6
NC6
RFIN_PCS
RFIN_PCS
17
17
2
NC7
NC7
VREG_PCS
VREG_PCS
18
18
1
C198
C198
C189
C189
4.7u
4.7u
1000p
1000p
RF5184
RF5184
U104
U104
C1002
C1002
2200p
2200p
VREG_RF_2.85V
VREG_RF_2.85V
L132
L132
C1005
C1005
C1006
C1006
1nH
1nH
2200p
2200p
1000p
1000p
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
PA_ON0
PA_ON0
VREG_RF_2.85V
VREG_RF_2.85V
FL105
FL105
4
5
EFCH836MTDB1
EFCH836MTDB1
L126
L126
O1
O1
G3
G3
1
IN IN
WCDMA_850_TX_OUT
WCDMA_850_TX_OUT
18nH
18nH
G2
G2
G1
G1
3
2
C187
C187
DNI
DNI
FL107
FL107
SAFEB1G95KA0F00
SAFEB1G95KA0F00
3
L128
L128
G3
G3
4
1
OUT
OUT
IN IN
WCDMA_2100_TX_OUT
WCDMA_2100_TX_OUT
2.7nH
2.7nH
G2
G2
G1
G1
5
2
C196
C196
C197
C197
DNI
DNI
DNI
DNI
VREG_RF_2.85V
VREG_RF_2.85V
PA_ON1
PA_ON1
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