LG -V909DW Service Manual page 25

3. TECHNICAL BRIEF
General
SMARTi™ UE is a highly integrated UMTS/GSM-transceiver, with all necessary features to enable multi
mode,multi band telephone applications. It incorporates a fully integrated dual mode receiver, multi band TX
outputs,TCVCXO control, a measurement interface, DigRF V3.09 compliant high speed data and control
interface, a multi mode timer unit and all necessary front end signals for the complete RF Engine control.
Overall the IC directly supports RF engines with up to 4 GSM bands and typ. 3 UMTS (can be less or more
depending on engine setup) bands without additional discrete RF path switches.
Receiver Section
For the RX section the IC features 5 RX inputs, 4 of those might be used for multi mode receive, this means
they can be used for GSM and UMTS (the IC can be reconfigured to achieve in spec performance) operation.
The band I input is for UMTS operation only. The multi mode inputs may alternatively be configured to be
first LNA (for GSM) or LNA2 (UMTS) when an additional external LNA and interstage filter is used. The receiver
structure is optimized for compressed mode operation, thus only a single base band chain is used, saving
area and optimizes power consumption.The receiver AGC can be aligned to the UMTS frame structure with
the TAS macro SYNC3G.
Transmitter Section
The TX features 6 RF outputs, which are directly matched to 50 Ω impedance for easy connection to external
power amplifiers, which reduces significantly external component count. 2 outputs are high power, small
signal polar modulated outputs for the GSM system, with low sensitivity to PA harmonics. They are capable
to perform GMSK or 8-PSK modulation signals with excellent noise performance, thus no interstage filter in
between transceiver and PA is required. The low band output covers the 850 MHz GSM bands, the mid band
output covers the 1800 and 1900 MHz bands.
The UMTS outputs are vector modulated single ended high output power driver amplifiers, with excellent
EVM and adjacent channel leakage performance. Together with external UMTS power amplifier modules all
bands except band VII can be addressed. There is one driver for all low bands (850 and 900 MHz bands), two
drivers for the mid bands (1700 - 1900 MHz bands) and one driver for the high band (2100 MHz band). Thus
many band combinations can be supported by the transceiver.
The IC features additionally closed loop power control for GSM and for UMTS, thus supporting TRP
requirements in cooperation with the power amplifier and the antenna design. There is one input pin for the
power detector voltage coming from the PA, the complete loop circuits are implemented in the digital
domain, which enables a high reliability of the loop performance for both standards.
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