adc10732 National Semiconductor Corporation, adc10732 Datasheet - Page 24

• Manufacturer Part Number: adc10732
• Description: 10-bit Plus Sign Serial I/o A/d Converters With Mux, Sample/hold And Reference
• Manufacturer: National Semiconductor Corporation

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3.4 Optional Adjustments
3.4.1 Zero Error
The zero error of the A/D converter relates to the location of
the first riser of the transfer function (see Figures 1, 2) and
can be measured by grounding the minus input and applying
a small magnitude voltage to the plus input. Zero error is the
difference between actual DC input voltage which is neces-
sary to just cause an output digital code transition from 000
0000 0000 to 000 0000 0001 and the ideal
LSB = 1.22 mV for V
REF
= + 2.500V).
(Continued)
FIGURE 15. Different Reference Configurations
Ratiometric Using the Internal Reference
1
⁄
2
LSB value (
Absolute Using a 4.096V Span
FIGURE 14.
1
⁄
2
24
The zero error of the A/D does not require adjustment. If the
minimum analog input voltage value, V
the effective “zero” voltage can be adjusted to a convenient
value. The converter can be made to output an all zeros
digital code for this minimum input voltage by biasing any
minus input to V
tial or pseudo-differential input channel configurations.
3.4.2 Full-Scale
The full-scale adjustment can be made by applying a differ-
ential input voltage which is 1
analog full-scale voltage range and then adjusting the V
IN
(Min). This is useful for either the differen-
01139029
1
⁄
2
LSB down from the desired
01139030
IN
(Min), is not ground,
REF