User's Manual

GE864- QUAD Har dwar e User Guide
1vv0300872 Rev.1 2010-04-02
- All Rights Reserved. Page 26 of 77
The table below shows the mod power consumptions:
GE864- QUAD
Mode
Aver age
(m A)
Mode descr iption
SWITCHED OFF
Module supplied but Switched Off
Switched Off
<62uA
IDLE mode
AT+CFUN=1
19,0
Nor mal mode: full functionality of the module
AT+CFUN=4
18,0
Disabled TX and RX; modul e is not register ed on the networ k
AT+CFUN=0 or =5
3,9
Paging Multifr ame 2
2,9
Paging Multifr ame 4
2,1
Paging Multifr ame 6
1,9
Paging Multifr ame 8
1,6
Paging Multifr ame 9
CSD TX and RX mode
GSM VOICE CALL
GSM900 CSD PL5
305,0
DCS1800 CSD PL0
208,0
GPRS (cl ass 10) 1TX
GPRS Sending data mode
GSM900 PL5
264,0
DCS1800 PL0
176,0
GPRS (cl ass 10) 2TX
GPRS Sending data mode
GSM900 PL5
473,8
DCS1800 PL0
307,8
The GSM system is made in a way that the RF transmission is not continuous, else it
is packed into bursts at a base fr equency of about 216 Hz, the relative cur r ent peaks
can be as high as about 2A. Ther efore the power supply has to be designed in order
to withstand with these cur r ent peaks without big voltage drops; this means that both
the electr ical 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
gr ound and the supply; this will reflect on all the audio paths producing an audible
annoying noise at 216 Hz; if the voltage drop dur ing the peak current absor ption is
too much, then the device may even shutdown as a consequence of the supply
voltage drop.
TIP:
The power supply must be designed so that it is capable of a peak current output of
at least 2 A.