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4.5.2 Transmitter: Power Amplifier
The output signals
power amplifier (Z900) passing a matching circuit. The PA is a "two in one" PA
(EGSM900/GSM1800) and is connected directly to Batt+. The band selection
switching is done via
output signals
(TX_PCN_OUT
coupler. The other part runs through the antenna switch (Z880) inside the FEM and
the antenna connector (X870) to the Antenna. The decoupled part is equalised by the
detector diode (V920) and used from the RF-Power regulator IC (D920) to get a PA
control voltage, by comparing this voltage with the PA_RAMP signal provided from the
EGOLD+ (
analogue interface J2
TXONPA
enables with a "high" signal the output "a" (pin 4).
The required voltage
The required voltage
from TX-
VCO
Blockdiagram of LML240 (PA control IC)
Vhom
e
Vdd
Vf
Vr
Ram
TC
Gnd
10 9 8 7 6
Top
view
1 2 3 4 5
V1.20
A55/C55_Hitachi
(PCN_PA_IN ,
and GSM_PA_IN) from the TX-VCO are led to the
GSM_ON
from the Bright IC. After amplification, a part of the
and TX_GSM_OUT) is decoupled via a directional
). The (N920) is activated through the signal TXON1.
BATT+
is provided by the battery.
VCC2_8
is provided by the ASIC D361.
Comp1
Company Confidential © Copyright Siemens AG
PA_ON
Vdd
Comp 2
Page 19 of 48
to Ant.
connector
BS
Vdd
Vss
Vdd
Vss
Vdd
Out
A
Vss
Vdd
Out B
Vss
ICM MP CCQ GRM
04/03
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