LISA-C2 series and FW75-C200 - System Integration Manual
UBX-13000620 - R21
Early Production Information
System description
Page 8 of 103
1.2
Architecture
1.2.1
LISA-C200 / FW75-C200
Wireless
Base-band
Processor
Memory
Power Management Unit
RF
Transceiver
19.2 MHz
Diplexer
ANT
LNA
3G PA
LNA
3G PA
UART
USB
GPIOs (**)
Power On
HW Reset (**)
Vcc (Supply)
V_INT (I/O)
(U)SIM
HW shutdown (*)
DDC
Digital Audio (I
2
S)
Figure 1: Block diagram: FW75-C200, LISA-C200
1.2.1.1
Functional blocks
LISA-C200 and FW75-C200 modules consist of the following internal functional blocks: RF front-end, RF
transceiver, baseband section, and power management unit.
RF Front-End
The antenna connector is directly connected to the diplexer, which separates the 800 and 1900 MHZ bands.
Each 800 & 1900 MHz RF chain is connected to its respective transceiver path via duplexers, as shown in the
block diagram.
Each duplexer provides the filtering and Rx/Tx path separation before connecting to the LNA and RF PA devices.
A separate shield compartment houses the 800 MHZ and 1900 MHZ RF power amplifiers. This compartment
provides high Tx signal isolation, preventing de-sensing of the Rx frontend circuitry.
RF Transceiver
The transceiver includes the following key components:
•
Dual-band 800 & 1900 MHz CDMA transceiver, excluding the RF Power Amplifiers, duplexers and diplexer.
•
19.2 MHz Crystal Oscillator
While operating, the RF transceiver performs direct up-conversion and down-conversion of the baseband I/Q
signals, with the RF voltage controlled gain amplifier being used to set the uplink TX power. In the downlink
path, the internal LNA enhances the RX sensitivity. An internal automatic gain control amplifier optimizes the
signal levels before delivering the analog I/Q to baseband for further digital processing.
The Rx path locks and tracks to the base station carrier. A learning algorithm is implemented to capture the
temperature characteristic of the xtal, comparing the XO and carrier frequencies, while measuring the thermistor
