User's Manual

GE865 Hardware User Guide

1vv0300799 Rev.6 - 04/06/09

5.3.1.3 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

GE865 module.

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

GE865 and damage it.

NOTE: DON'T USE any Ni-Cd, Ni-MH, and Pb battery types directly connected with GE865. Their use can

lead to overvoltage on the GE865 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 GE865 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.