Wcdma Mode - LG L602i Service Manual

3. TECHNICAL BRIEF

3.3 WCDMA Mode

3.3.1 Receiver
The UMTS duplexer receiver output is routed to LNA circuits within the RFL6202 IC. These LNA
functions are removed from the RFR6202 IC to improve mixer LO to RF isolation. The LNA gain is
dynamically controlled by the MSM device to cover full receiver dynamic range and to save current
consumption.
The UMTS LNA output is routed to the RFR6202 through a band selection filter that transforms a
single-ended 50Ω source to differential 100-Ω load impedance that is matched to the RFR6202 IC. The
RFR input uses a differential configuration to improve secondorder inter-modulation and common mode
rejection performance. The RFR6202 IC input stages include MSM-controlled gain adjustments that
further extend receiver dynamic range.
The amplifier output drives the RF port of the quadrature RF-to-baseband down-converter. The down-
converted baseband outputs are routed to lowpass filters (one I and one Q) having pass-band and stop-
band characteristics suitable for DS-WCDMA processing. The filter outputs are buffered and passed on
to the MSM6250A IC for further processing. This baseband interface is shared with the RTR6250 GSM
receiver outputs.
Figure 1.3.1-1 RFL6202 IC functional block diagram
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