User's Manual

HE910 Hardware User Guide
1vv0300925 Rev.28 – 2015-06-24
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 34 of 34
5.2 Power Consumption
HE910
Mode
Average
(mA)
Mode description
SWITCHED OFF
Module supplied but Switched Off
Switched Off 40uA
IDLE mode (WCDMA)
AT+CFUN=1 12.2 Normal mode: full functionality of the module
AT+CFUN=5 1.2
Full functionality with power saving; DRX7;
Module registered on the network can receive incoming calls
and SMS
IDLE mode (GSM/EDGE)
AT+CFUN=1 19 Normal mode: full functionality of the module
AT+CFUN=4 16.5 Disabled TX and RX; module is not registered on the network
AT+CFUN=5 0.8
Full functionality with power saving;
DRX9 (1.3mA in case of DRX5).
Operative mode (WCDMA)
WCDMA Voice 152 WCDMA voice call (TX = 10dBm)
WCDMA HSDPA (0dBm) 187 WCDMA data call (Cat 14, TX = 0dBm)
WCDMA HSDPA (22dBm) 494 WCDMA data call (Cat 14, TX = 22dBm)
Operative mode (EDGE)
EDGE 4TX+2RX
EDGE Sending data mode GSM900 PL5 495
DCS1800 PL0 484
Operative mode (GSM)
CSD TX and RX mode
GSM VOICE CALL GSM900 CSD PL5 220
DCS1800 CSD PL0 167
GPRS 4TX+2RX
GPRS Sending data mode GSM900 PL5 580
DCS1800 PL0 438
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.