Rtc Backup; Control Signals; Figure 1: Rtc Supply From Capacitor For Tc35I; Figure 2: Rtc Supply From Capacitor For Tc35 - Siemens TC35i Migration Manual

TC35i: Migration from TC35 to TC35i
P R E L I M I N A R Y
4.5

RTC backup

The internal Real Time Clock of is supplied from a dedicated voltage regulator in the power
supply ASIC which is also active when TC35 and TC35i are in POWER DOWN status. Alarm
function is included that allows waking up TC35 and TC35i without logging to the GSM
network.
On the TC35i board a serial resistor is placed next to the VDDLP line in order to limit
the input current of an empty capacitor. This eliminates the need of adding a resistor
as required in applications based on the earlier TC35 module.
On the TC35 board there is no resistor placed on the board and it should be added when
designing the GSM application

Figure 1: RTC supply from capacitor for TC35i

Figure 2: RTC supply from capacitor for TC35

4.6

Control signals

Input and Output control signals are identical with both TC35 and TC35i device.
For further information please consult the HW manual for TC35 and TC35i.
TC35_TC35i_MIG_01_V01.01
Baseband
processor
PSU
RTC
29.1.2003
BATT+
ZIF
1 k
VDDLP
+
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