User's Manual
LE920 Hardware User Guide
1vv0301026 Rev.8 2015-01-03
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights
Reserved. Page 41 of 88
5.2.1.3. 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 suited for supplying
the power to the Telit LE920 module.
NOTE:
Do not use any Ni-Cd, Ni-MH, and Pb battery types directly connected with LE920. Their use
can lead to overvoltage on LE920 and damage it. Use only Li-Ion battery types.
A bypass low ESR capacitor of adequate capacity must be provided in order to
cut the current absorption peaks; a 100μF tantalum capacitor is usually suitable
(on both VBATT and VBATT_PA together).
Make sure the low ESR capacitor (usually a tantalum one) is rated at least 10V.
A protection diode must be inserted close to the power input, in order to protect
LE920 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 900mAh in order to withstand the current
peaks of 2A.