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V 1.0 Page 7of 52 ICM MP CCQ GRM
SL55
Company Confidential © Copyright Siemens AG
06/03
4.1 Power Supply RF-Part
The voltage regulator for the RF-part is located inside the ASIC D361.(see chapter 5.2).It
generates the required 2,85V “RF-Voltages” named VREGRF1 and VREGRF2.
The following components are supplied by:
VREGRF1
· 26 MHz reference oscillator
· VCO
· PLL
VREGRF2
· Modulators
· RX mixers
· Limiter amplifier
The voltage regulator RFREG 1 is controlled by 1.8V (RF_EN
(RF REG G2)), RFREG2 is
controlled by SLEEP1_N
(on/off Control H1) and SLEEP2_N (on/off Control F1). IF one of these
signals is high the regulator is enable. SLEEP1_N is connected to the signal VCXOEN
(Miscellaneous R6) provided by the EGOLD+. RF_EN and SLEEP2_N is connected to 1.8 V
provided by the ASIC (REG2 A7) The temporary deactivation is used to extend the stand by
time.
Circuit diagram
4.2 Frequency generation
4.2.1 Synthesizer: The discrete VCXO (26MHz)
The SL55 mobile phone is using a reference frequency of 26 MHz signal that is created by
a partly integrated VCXO. ON/OFF signal (VCXOEN
(Miscellaneous R6)) comes from the
EGOLD+. A Colpitts-oscillator is used with a post connected buffer stage integrated in the
Smarti. For temperature measurements of the VCXO a temperature resistance (R700) is
used. The resistor is placed near the VCXO. The measurement result TVCXO is reported
to the EGOLD+
(Analog Interface P3) via R138 as the signal TENV.
The frequency of the reference oscillator can be adjusted by the EGOLD+ via a PNM-
modulated AFC-signal.
The signal leaves the SMARTI as BB_SIN26M at pin 4 to be further used from the
EGOLD+ (D171
(functional T3)).
The required voltage VREGRF1 is provided by the ASCI D361
REGRF1
REGRF2
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