User's Manual

LE940B6 Hardware User Guide
1VV0301331 Rev. 1.8 - 2017-03-15
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Mode Average (Typ.) Mode Description
GSM 1800/1900
PL0
300 mA
GPRS 4 Tx + 1 Rx
GSM 850/900 PL5 750 mA
GPRS Sending Data mode (CS-4)
DCS 1800/1900 PL0 550 mA
EGPRS 4 Tx + 1 Rx
GSM 850/900 PL8 550 mA
GPRS Sending Data mode (MCS-5)
DCS 1800/1900 PL2 500 mA
* Worst/best case current values depend on network configuration, not under module control.
** Applied MPR –2dB 16-QAM full RB
*** 3.8V voltage/room temperature
NOTE:
Differences in measurement technique, equipment, or temperature can cause variations in
current consumption measurements.
NOTE:
The electrical design for the power supply must ensure a peak current output of at least 2.0A.
NOTE:
In GSM/GPRS mode, RF transmission is not continuous, but is packed into bursts at a base
frequency of about 216 Hz with relative current peaks as high as about 2.0A. Therefore, the
power supply must be designed 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 peaks, current absorption is too high. The device may even shut
down as a consequence of the supply voltage drop.