User's Manual

UE910 V2 Hardware User Guide
1VV0301065 Rev.1 – 2013-12-12
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved. Page 27 of 67
5.2. Power Supply Requirements
Current Consumption
Mode
Average
(mA)
Mode Description
Power off current (Typical)
< 10uA
Standby mode
No call in progress
AT+CFUN=1
22
Normal mode; full functionality of the module
AT+CFUN=4
20
Disabled TX and RX; modules is not registered on the
network
AT+CFUN=0
or
AT+CFUN=5
4.8/1.2*
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 call sand SMS
Tx and Rx mode
A call in progress
Max Power Mode
700
WCDMA/HSDPA voice/data call
Max Power Mode
700
440
EU : GPRS Class12
NA : GPRS Class10
Max Power Mode
420
270
EU : EGPRS Class12
NA : EGPRS Class10
*Worst/best case depends on network configuration and is not under module control.
TIP:
The electrical design for the power supply should be made ensuring it will be capable of a peak
current output of at least 2A.
In GSM/GPRS mode, RF transmission is not continuous and 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 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; this will
reflect on all the audio paths producing an audible annoying noise at 216 Hz; if the voltage drops
during the peak, current absorption is too much. The device may even shut down as a consequence of
the supply voltage drop.