Datasheet

ST72321Rx ST72321ARx ST72321Jx
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10-BIT ADC CHARACTERISTICS (Cont’d)
12.12.3 ADC Accuracy
Conditions: V
DD
=5V
1)
Notes:
1. ADC Accuracy vs. Negative Injection Current: Injecting negative current may reduce the accuracy of the conversion
being performed on another analog input.
Any positive injection current within the limits specified for I
INJ(PIN)
and ΣI
INJ(PIN)
in Section 12.8 does not affect the ADC
accuracy.
2. Data based on characterization results, monitored in production to guarantee 99.73% within ± max value from -40°C
to 125°C (± 3σ distribution limits).
Figure 100. ADC Accuracy Characteristics
Symbol Parameter Conditions Typ
Max
2)
Unit
|E
T
| Total unadjusted error
1)
34
LSB
|E
O
| Offset error
1)
23
|E
G
| Gain Error
1)
0.5 3
|E
D
| Differential linearity error
1)
CPU in run mode @ f
ADC
2 MHz.
12
|E
L
| Integral linearity error
1)
CPU in run mode @ f
ADC
2 MHz.
12
E
O
E
G
1LSB
IDEAL
1LSB
IDEAL
V
AREF
V
SSA
–
1024
--------------------------------------------=
V
in
(LSB
IDEAL
)
(1) Example of an actual transfer curve
(2) The ideal transfer curve
(3) End point correlation line
E
T
=Total Unadjusted Error: maximum deviation
between the actual and the ideal transfer curves.
E
O
=Offset Error: deviation between the first actual
transition and the first ideal one.
E
G
=Gain Error: deviation between the last ideal
transition and the last actual one.
E
D
=Differential Linearity Error: maximum deviation
between actual steps and the ideal one.
E
L
=Integral Linearity Error: maximum deviation
between any actual transition and the end point
correlation line.
Digital Result ADCDR
1023
1022
1021
5
4
3
2
1
0
7
6
1234567
1021 1022 1023 1024
(1)
(2)
E
T
E
D
E
L
(3)
V
AREF
V
SSA