GL865 Hardware User Guide
1vv0300910 Rev.1 – 2011-07-22
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved
page 28 of 79
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
GL865 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 GL865 and damage
it.
NOTE:
DON'T USE any Ni-Cd, Ni-MH, and Pb battery types directly
connected with GL865. Their use can lead to overvoltage on the
GL865 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 100
µ
F 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 GL865 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.