
ST7L34, ST7L35, ST7L38, ST7L39
Electrical characteristics
Doc ID 11928 Rev 7
Figure 103. ADC accuracy characteristics
1.
Legend:
ET = Total unadjusted error: maximum deviation between the actual and the ideal transfer curves
EO = Offset error: deviation between the first actual transition and the first ideal one
EG = Gain error: deviation between the last ideal transition and the last actual one
ED = Differential linearity error: maximum deviation between actual steps and the ideal one
EL = Integral linearity error: maximum deviation between any actual transition and the end point correlation
line
2.
Data based on characterization results over the whole temperature range, monitored in production.
3.
ADC accuracy vs negative injection current: Injecting negative current on any of the analog input pins may
reduce the accuracy of the conversion being performed on another analog input.
Any positive injection current within the limits specified for IINJ(PIN) and ΣIINJ(PIN) in Section 13.8: I/O port Table 126.
ADC accuracy with 3 V < VDD < 3.6 V
Symbol
Parameter
Conditions
Typ
Max(1)
1.
Data based on characterization results, monitored in production to guarantee 99.73 % within ± max value
from -40 °C to +125 °C (± 3
σ distribution limits).
Unit
|ET|
Total unadjusted error
fCPU = 4 MHz, fADC = 2 MHz
(2)(3)
2.
Data based on characterization results over the whole temperature range, monitored in production.
3.
ADC accuracy vs negative injection current: Injecting negative current on any of the analog input pins may
reduce the accuracy of the conversion being performed on another analog input.
Any positive injection current within the limits specified for IINJ(PIN) and ΣIINJ(PIN) in Section 13.8: I/O port 1.9
3.1
LSB
|EO|
Offset error
0.3
1.2
|EG|
Gain error
0.3
1
|ED|
Differential linearity error
1.8
3
|EL|
Integral linearity error
1.7
2.8
EO
EG
1LSBIDEAL
1LSB
IDEAL
V
DD
V
SS
–
1024
--------------------------------
=
Vin (LSBIDEAL)
Digital result ADCDR
1023
1022
1021
5
4
3
2
1
0
7
6
1
2
34
56
7
10211022 1023 1024
(1)
(2)
ET
ED
EL
(3)
VDD
VSS
(1) = Example of an actual transfer curve
(2) = Ideal transfer curve
(3) = End point correlation line