User's Manual

UE910 3G HARDWARE USER GUIDE 1vv0301171 Rev.3 • 2015-04-17 24 of 78
Reproduction forbidden without Telit Communications PLC written authorization – All Rights Reserved
Battery Source Power Supply Design Guidelines
The desired nominal output for the power supply is 3.8V and the maximum voltage allowed is 4.2V,
hence a single 3.7V Li-Ion cell battery type is suited for supplying the power to the Telit UE910 module.
 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 suited.
 Make sure the low ESR capacitor (usually a tantalum one) is rated at least 10V.
 A protection diode should be inserted close to the power input, in order to save the UE910 from
power polarity inversion. Otherwise the battery connector should be done in a way to avoid
polarity inversions when connecting the battery.
 The battery capacity must be at least 500mAh in order to withstand the current peaks of 2A;
the suggested capacity is from 500mAh to 1000mAh.
WARNING:
The three cells Ni/Cd or Ni/MH 3,6 V Nom. battery types or 4V PB types MUST
NOT BE USED DIRECTLY since their maximum voltage can rise over the
absolute maximum voltage for the UE910 and damage it.
NOTE:
DON'T USE any Ni-Cd, Ni-MH, and Pb battery types directly connected with
UE910. Their use can lead to overvoltage on the UE910 and damage it. USE
ONLY Li-Ion battery types.