User's Guide

UL865 Hardware User Guide
1VV0301050 Rev 2 – 2013-10-09
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 UL865 module.
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 UL865 and damage it.
NOTE:
DON'T USE any Ni-Cd, Ni-MH, and Pb battery types directly connected with UL865.
Their use can lead to overvoltage on the UL865 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 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 UL865
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.