User Guide

The DCDC converter limits the lowest supply voltage to 1.5 V. At highest power levels the DCDC converter output

settles nominally to 3.2 V.

Figure 117 Block diagram of DCDC converter and WCDMA PA

GSM transmitter

An analogue IQ modulated signal is received to N7501 from digital BB.

The signal is first low pass filtered with filter corner frequency set to approximately 200 kHz. After the filter, the

signal is routed to the GSM modulator.

The appropriate routing after the modulator is selected by biasing either EGSM900 or GSM1800/1900 variable

gain amplifier. The amplifier gives 40 dB of power control dynamic range.

After the VGA stage the signal exits N7501. In case of GSM1800/1900 the signal goes directly to the GSM PA

module. In case of EGSM900, the PA module is preceded by a SAW filter. After the filter, the signal is fed to GSM

PA module. Finally the signal is routed via antenna switch to the antenna.

RM-1

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