ADUC834: Should I use the internal voltage reference or an external voltage reference?

Document created by analog-archivist Employee on Feb 23, 2016
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The ADuC834 features an internal voltage reference but I have been recommended
to use an
external voltage reference. Is this correct? If so why is the internal
reference present?


Yes, we do recommend that an external voltage reference is used for the
applications that require
good ADC accuracy. Typically the internal voltage reference is only 13-14 bit
accurate and will
not be useful for most applications. The WASP (available as part of the
QuickStart? Development
System) allows you to compare the noise performance of the ADuC834 with an
internal and an
external voltage reference.
The internal voltage reference is often used with the auxiliary ADC where the
very high accuracy
might not be required. Often the primary ADC is used with a ratiometric voltage
reference which
will be useless for another measurement. In this case the internal reference
can be used for the
second measurement. The internal voltage reference is also necessary for the
internal temperature