3. TECHNICAL BRIEF
- 23 -
Copyright © 2012 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
DNI
C370
L300
33n
FILKOR
C362
DNI
R370
22
ANT300
L302 1n
L399
2.2n
C397
33
C308
1
DNI
L392
C316
1n
L305
33n
FILKOR
2.2nL313
FILKOR
33n
C303
C361
4.7p
C360
3.9p
10K R392
R394
DNI
C307
100p
SMRH0007101
U300
SKY77550
29
23
24
25
26
27
28
15
16
17
18
19
20
21
22
8
7
6
5
4
3
2
1
14
13
12
11
10
9
Tx_LB_IN
Tx_HB_IN
VSW_EN
BS
RSVD1
RSVD2
GND1
GND2
VBATT1
VBATT2
GND3
GND4
GND5
GND6
GND7
Rx2
RSVD3
Rx1
RSVD
TxEN
VRAMP
GND8
GND9
GND10
ANT
GND11
GND12
GND13
PGND
L314
0.5p
C305
1p
VBAT
22p
C350
220p
C304
1
2
L310 1n
12n
L381
L350
3.6n
24K
R391
33p
C311
DNIC312
DNI
C301
C302
33p
L390
10n
12nL380
2.2p
C306
2.2p
C300
C310
1.5p
1.5pC317
L308 3.3n
L311
3.3n
L312
5.6n
ANT301
L391
10n
C321
68n
3.6n
L351
C3994.7u
4.7u C398
5.6n
L306
SW300
G2
ANT
RF
G1
RF_TX_RAMP
RF_TX_EN
RF_LB_TX
RF_HB_RXN
RF_HB_RXP
GND
RF_HB_TX
RF_2G_BS
RF_LB_RXN
RF_VLOGIC
RF_LB_RXP
4.7uF,10V ,M ,X5R ,HD ,1608 ,R/TP
Mode
Input Control Bits
VSW_EN TxEN BS
STANDBY 0 0 0
Rx1
1
1 0 0
Rx2
2
1 0 1
Tx_LB 1 1 0
Tx_HB 1 1 1
Rx1 and Rx2 are broadband receive ports and each supports the GSM850, GSM900, DCS, and PCS bands.
Band selection and control of transmit and receive are performed using four external control pads. Refer to the block
diagram in Figure 1 below. The band select pad, BS, selects GSM850, GSM900, DCS, and PCS modes of operation. Transmit
enable TxENcontrols receive or transmit mode of the RF switch (Tx= logic 1). Proper timing between transmit enable
TxENand Analog Power Control VRAMP allows for high isolation between the antenna and Tx–VCO while the VCO is
being tuned prior to thetransmit burst. The SKY77550 is compatible with logic levels from 1.2 V to 2.9 V for BS, TxEN, and
VSW_EN pads.
Figure 3.3.2 Band SW Logic TableFigure
Figure 3.3.3 FEM CIRCUIT DIAGRAM
To Next Page
Loading...
