LISA-U2 series - System integration manual
UBX-13001118 - R27
System description
Page 9 of 183
C1-Public
1.2
Architecture
Wireless
Base-band
Processor
Memory
Power Management Unit
26 MHz
32.768
kHz
ANT
Switch & Multi band & mode PA
DDC (for GNSS)
(U)SIM card
UART
SPI
USB
GPIO(s)
Power on
External reset
V_BCKP (RTC)
Vcc (supply)
V_INT (I/O)
Digital audio (I
2
S)
RF
SWITCH
RF
Transceiver
Duplexers
& Filters
ANT_DIV
RF
SWITCH
Filter
Bank
PA
PM
U
Transceiver
PMU
Figure 1: LISA-U2 series block diagram (for available options see
1.2.1
Functional blocks
LISA-U2 modules consist of the following internal functional blocks: RF section, Baseband and Power
Management Unit section.
LISA-U2 series RF section
A shielding box contains the RF high-power signal circuitry, including:
•
Multimode Single Chain Power Amplifier Module used for 3G HSPA/WCDMA and 2G EDGE/GSM
operations
•
Power Management Unit with integrated DC/DC converter for the Power Amplifier Module
The RF antenna pad (
ANT
) is directly connected to the main antenna switch, which dispatches the RF
signals according to the active mode. For time-duplex 2G operation, the incoming signal at the active
receiver (RX) slot is applied by the main antenna switch to the duplexer SAW filter bank for out-of-
band rejection and then sent to the appropriate receiver port of the RF transceiver. During the
allocated Transmitter (TX) slots, the low level signal coming from the RF transceiver is enhanced by
the power amplifier and then directed to the antenna pad through the main antenna switch. The 3G
transmitter and receiver are active at the same time due to frequency-domain duplex operation. The
switch integrated in the main antenna switch connects the antenna port to the duplexer SAW filter
bank which separates the TX and RX signal paths. The duplexer itself provides front-end RF filtering
for RX band selection while combining the amplified TX signal coming from the power amplifier.
A separated shielding box contains all the other analog RF components, including:
•
Antenna switch and duplexer SAW filter bank for main paths
•
Antenna switch and SAW filter bank for diversity receiver
•
Up to six-band HSPA/WCDMA and quad-band EDGE/GPRS/GSM transceiver
