GSM power amplifier
5.3.3
The output signals (OUT1 and OUT2) from the GSM TX VCO are led to the power amplifier.
The power amplifier is the PA-module N300. It contains of two separate amplifier chains for
GSM900 and GSM1800/GSM1900 operation. The amplification is controlled with the signal
VRAMP. The appropriate amplifier chain is activated by the logic signal GSM_PA__BAND
which is provided by the MSM6250. The N300 is activated through the signal VTXB, which
is the level shifted GSM_PA_EN provided by the MSM6250.
The voltage VBATT is provided by the battery.
to antenna
switch
Circuit diagram (sheet 3)
Technical Documentation
TD_Repair_L3_SXG75_R1.0.pdf
VBATT
GSM_PA_BAND
Company Confidential
2006©BenQ
Release 1.0
GSM_PA_EN
(level shifted)
PA RAMP
OUT2 from TX VCO
OUT1 from TX VCO
01/2006
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