LE940B6 HW User Guide
Rev. 2.02
Page 63 of 111
2020-01-10
6.2.1.3.
Battery Source Power Supply
– Design Guidelines
•
The desired nominal output for the power supply is 3.8V, and the maximum
allowed voltage is 4.2V. Hence, a single 3.7V Li-Ion cell battery type is suitable for
supplying the power to the LE940B6 module.
NOTE:
Do not use any Ni-Cd, Ni-MH, and Pb battery types directly connected to the
LE940B6 module. Their use can lead to overvoltage on the LE940B6 and
damage it. Use only Li-Ion battery types.
•
A bypass low ESR capacitor of adequate capacity must be provided to cut the
current absorption peaks; a 100μF tantalum capacitor is usually suitable.
•
Make sure that the low ESR capacitor (usually a tantalum one) is rated at least
10V.
•
A protection diode must be inserted close to the power input to protect the
LE940B6 module from power polarity inversion. Otherwise, the battery connector
must be done in a way to avoid polarity inversions when connecting the battery.
•
The battery capacity must be at least 500 mAh to withstand the current peaks of
2A. The suggested capacity is from 500 mAh to 1000 mAh.
6.2.2.
Thermal Design Guidelines
The thermal design for the power supply heat sink must be done with the following
specifications:
•
Average current consumption during LTE 2xCA DL Max throughput @PWR level
max in LE940B6: 1250
mA
NOTE:
The average consumption during transmission depends on the power level
at which the device is requested to transmit via the network. Therefore, the
average current consumption varies significantly.
In LTE mode, the LE940B6 emits RF signals continuously during transmission. Therefore,
pay special attention to how the generated heat is dissipated.
The current consumption is up to about 1250 mA in 2xCA Max throughput, and 1250 mA
in LTE continuously at the maximum Tx output power 23.0 dBm.
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