Owner's manual

GM862-GPS Hardware User Guide

1vv0300728 Rev. 8 - 20/09/07

6.2.1.3 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

GM862-GPS 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

GM862-GPS and damage it.

NOTE: DON'T USE any Ni-Cd, Ni-MH, and Pb battery types directly connected with GM862-GPS. Their use can lead

to overvoltage on the GM862-GPS 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 GM862-GPS

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.