User's Guide

UC864-E-AUTO / AWS-AUTO Hardware User Guide

1vv0300795 Rev.11 – 2010/11/18

6.2.1.3. Battery Source Power Supply Design Guidelines

• The desired nominal output for the power supply is 3.8V and the

maximum allowed voltage is 4.2V, hence a single 3.7V Li-Ion cell battery

type is suited for supplying the power to the Telit UC864-E-AUTO / AWS-

AUTO 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 UC864-E-AUTO / AWS-AUTO

and damage it.

• 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 must be inserted close to the power input, in order to

save UC864-E-AUTO / AWS-AUTO from power polarity inversion.

Otherwise the battery connector must 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.

NOTE:

NOTE: NOTE:

NOTE:

Do not use any Ni-Cd, Ni-MH, and Pb battery types directly connected with UC864-E-

AUTO / AWS-AUTO. Their use can lead to overvoltage on UC864-E-AUTO / AWS-AUTO

and damage it. Use only Li-Ion battery types.