User Guide

HE910 Hardware User Guide

1vv0300925 Rev.18 – 15-06-2012

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 HE910 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 HE910 and damage it.

NOTE:

DON'T USE any Ni-Cd, Ni-MH, and Pb battery types directly connected with HE910. Their use

can lead to overvoltage on the HE910 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 HE910 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.