Power Supply Rf-Part; Frequency Generation - Siemens A70 Service Repair Documentation

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6.2 Power Supply RF-Part

The voltage regulator for the RF-part is located inside the
required 2,8V "RF-Voltages" named
resistor and renamed as
regulator is activated as well as deactivated via
provided by the EGOLDlite. The temporary deactivation is used to extend the stand by
(M4)
time.
Circuit diagram

6.3 Frequency generation

Synthesizer: The discrete VCXO (26MHz)
The A70/A75 mobile is using a reference frequency of 26MHz. The generation of the 26MHz
signal is done via a VCO (Z950).
TP (test point) of the 26MHz signal is the TP 820
The oscillator output signal 26MHz_RF is directly connected to the BRIGHT IC
be used as reference frequency inside the Bright (PLL). The signal leaves the Bright IC as
RF_SIN26M
(ball G9)
TD_Repair_L2.5_A70_A75_R1.0.pdf
VDD_RF1
VDD_BRIGHT
to be further used from the EGOLDlite
and VDD_RF2.
as operating voltage for the BRIGHT. The voltage
SLEEPQ
Page of
11 53
s Com
ASIC D361.It generates the
VDD_RF2 is passed via a 0Ω
and
(TDMA-Timer R11)
(D171 ).
(C8)
VCXOEN_UC
VDD_RF1
VDD_RF2
to
(ball B9,. C9)
Release 1.0