User Manual

GE863-PRO
3
Hardware User Guide
1vv0300773a Rev. 1 DRAFT - 24/04/08
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 24 of 82
5 Power Supply
The power supply circuitry and board layout are a very important part in the full product design and
they strongly reflect on the product overall performances, hence read carefully the requirements and
the guidelines that will follow for a proper design.
In the GE863-PRO
3
the power supply inputs of the GSM engine and the ARM processor part have
been kept separate, VBATT is the input for the GSM part, VBATT2 is the input for ARM.
It is possible to connect together the two power inputs since they have compatible ranges, but if it is
desired the two power supplies can be kept separate.
The only power supply in common between the ARM and GSM engine is the RTC voltage which is
generated by the GSM engine from VBATT power source and supplies both the GSM RTC and the
ARM VDDBU part including the shutdown controller, rtc, 32 KHz oscillator. For this reason if it is
planned to remove VBATT power supply, then a backup battery shall be provided on VTRC pin that
guarantees that VRTC is still available.
NOTE: if you plan to remove VBATT power source, then you must provide an appropriate backup
battery/capacitor on the VRTC pin in order to be able to turn on properly the ARM part when supplying
VBATT2 only power pin.
5.1 GSM Power Supply Requirements
POWER SUPPLY
Nominal Supply Voltage 3.8 V
Max Supply Voltage 4.2 V
Supply voltage range 3.4 V - 4.2 V
GE863-PRO3 GSM Engine
Mode Average (mA) Mode description
IDLE mode
Stand by mode; no call in progress
AT+CFUN=1 24,0 Normal mode: full functionality of the module
AT+CFUN=4 22,0 Disabled TX and RX; module is not registered on the network
AT+CFUN=0 or
AT+CFUN=5
7,20 / 3,56
1
Power saving: CFUN=0 module registered on the network and can
receive voice call or an SMS; but it is not possible to send AT
commands; module wakes up with an unsolicited code (call or
SMS) or rising RTS line. CFUN=5 full functionality with power
saving; module registered on the network can receive incoming
calls and SMS
RX mode
1 slot in downlink 53,0
2 slot in downlink 66,0
3 slot in downlink 79,0
4 slot in downlink 89,0
GSM Receiving data mode
1
Worst/best case depends on network configuration and is not under module control