Applications Information
(Continued)
reference voltage at the corresponding “−” input should then
be adjusted to just obtain the 00
HEX
to 01
HEX
code transition.
LSB is calculated for the desired analog span, 1 LSB = ana-
log span/256) is applied to selected “+” input and the zero
DS005016-16
a) Ratiometric
b) Absolute with a Reduced Span
FIGURE 2. Referencing Examples
The full-scale adjustment should be made [with the proper
V
IN
(−) voltage applied] by forcing a voltage to the V
IN
(+) in-
put which is given by:
DS005016-17
The V
REF
(or V
CC
) voltage is then adjusted to provide a code
change from FE
HEX
to FF
HEX
. This completes the adjust-
ment procedure.
For an example see the Zero-Shift and Span Adjust circuit
below.
where V
MAX
= the high end of the analog input range and
V
MIN
= the low end (the offset zero) of the analog range. (Both
are ground referenced.)
Zero-Shift and Span Adjust (2V≤V
IN
≤5V)
DS005016-18
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