User Guide

GE9
GE9GE9
GE910 Hardware User Guide
10 Hardware User Guide10 Hardware User Guide
10 Hardware User Guide
1vv0300962 Rev.4 2012-06-25
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 27 of 73
Mod. 0805 2011-07 Rev.2
5.2. Power Consumption
The GE910 power consumptions are:
GE910
Mode
Average
(mA)
Mode description
SWITCHED OFF
Switched Off Typical 60uA
Module supplied but Switched Off
IDLE mode
AT+CFUN=1 21 Normal mode: full functionality of the module
AT+CFUN=4 18 Disabled TX and RX; module is not registered on the network
3,8 Paging Multiframe 2
2,5 Paging Multiframe 3
2,4 Paging Multiframe 4
AT+CFUN=0 or =5
1,2 Paging Multiframe 9
CSD TX and RX mode
GSM900 CSD PL5 230
DCS1800 CSD PL0 175
GSM VOICE CALL
GPRS (class 1) 1TX + 1RX
GSM900 PL5 225
DCS1800 PL0 160
GPRS Sending data mode
GPRS (class 10) 2TX + 3RX
GSM900 PL5 360
DCS1800 PL0 290
GPRS Sending data mode
The GSM system is made in a way that the RF transmission is not continuous, else it is packed
into bursts at a base frequency of about 216 Hz, and the relative current peaks can be as high as
about 2A. Therefore the power supply has to be designed in order to withstand with these
current peaks without big voltage drops; this means that both the electrical design and the board
layout must be designed for this current flow.
If the layout of the PCB is not well designed a strong noise floor is generated on the ground and
the supply; this will reflect on all the audio paths producing an audible annoying noise at 216
Hz; if the voltage drop during the peak current absorption is too much, then the device may even
shutdown as a consequence of the supply voltage drop.
NOTE:
The electrical design for the Power supply should be made ensuring it will be capable of a peak
current output of at least 2 A.