User's Manual

LE910 Hardware User Guide
1vv0301089 Rev.3 – 09-06-2014
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 28 of 79
LE910 current consumption
Mode
Average (mA)
Mode description
SWITCHED OFF
Module supplied but Switched Off
Switched Off
40uA
IDLE mode (GSM/EDGE)
AT+CFUN=1
WCDMA
16
Normal mode: full functionality of the module
GSM
16
LTE
16
AT+CFUN=4
10
Disabled TX and RX; module is not registered on the
network
AT+CFUN=5
WCDMA
1.7
Full functionality with power saving;
GSM
1.9
Operative mode (LTE)
LTE (0dBm)
203
LTE data call (channel BW 5MHz, RB=1, TX=0dBm)
LTE (22dBm)
540
LTE data call (channel BW 5MHz, RB=1, TX=22dBm)
Operative mode (WCDMA)
WCDMA Voice
185
WCDMA voice call (TX = 10dBm)
WCDMA HSDPA (0dBm)
100
WCDMA data call (RMC, TX = 0dBm)
WCDMA HSDPA (22dBm)
390
WCDMA data call (RMC, TX = 22dBm)
Operative mode (EDGE)
EDGE 4TX+1RX
EDGE Sending data mode
LOW Band PL5
255
High Band PL0
240
Operative mode (GSM)
GSM TX and RX mode
GSM VOICE CALL
LOW Band CSD PL5
290
High Band CSD PL0
170
GPRS 4TX+1RX
GPRS Sending data mode
LOW Band PL5
410
High Band PL0
320
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 2A.