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User's Guide

ManualsBrandsTelit Communications ManualsElectronicsGSM 850, E-GSM 900, DCS 1800, PCS 1900, FDD IV, 2G/3.5G module
41424344454647484950
UC864-E-AUTO / AWS-AUTO Hardware User Guide
1vv0300795 Rev.11 – 2010/11/18
Reproduction forbidden without Telit Communications S.p.A’s. written authorization - All Rights Reserved. Page 47 of 78
A power source of the internal interface voltage corresponding to the 2.6V CMOS high
level is available at the VAUX pin on the connector.
A maximum of 9 resistors of 47 KΩ pull-up can be connected to the VAUX pin,
provided no other devices are connected to it and the pulled-up lines are UC864-E-
AUTO / AWS-AUTO input lines connected to open collector outputs in order to avoid
latch-up problems on UC864-E-AUTO / AWS-AUTO.
Careful approach is needed to avoid latch-up on UC864-E-AUTO / AWS-AUTO and the
use of this output line to power electronic devices must be avoided, especially for
devices that generate spikes and noise such as switching level translators, micro
controllers, failure in any of these condition can severely compromise the UC864-E-
AUTO / AWS-AUTO functionality.
NOTE:
NOTE: NOTE:
NOTE:
The input lines working at 2.6VCMOS can be pulled-up with 47KΩ resistors that can
be connected directly to the VAUX line. It is a must that they are connected as in this
example.
The preferable configuration is having external supply for the buffer.