Electrical characteristics
STM32F103x8, STM32F103xB
(1) (2) (3)
Table 48. ADC accuracy
Symbol
Parameter
Test conditions
Typ
Max(4)
Unit
ET
EO
EG
ED
EL
Total unadjusted error
Offset error
2
5
2.5
3
fPCLK2 = 56 MHz,
fADC = 14 MHz, RAIN < 10 k,
VDDA = 2.4 V to 3.6 V
1.5
1.5
1
Gain error
LSB
Measurements made after
ADC calibration
Differential linearity error
Integral linearity error
2
1.5
3
1. ADC DC accuracy values are measured after internal calibration.
2. Better performance could be achieved in restricted VDD, frequency and temperature ranges.
3. ADC Accuracy vs. Negative Injection Current: Injecting negative current on any of the standard (non-
robust) analog input pins should be avoided as this significantly reduces the accuracy of the conversion
being performed on another analog input. It is recommended to add a Schottky diode (pin to ground) to
standard analog pins which may potentially inject negative current.
Any positive injection current within the limits specified for IINJ(PIN) and IINJ(PIN) in Section 5.3.12 does not
affect the ADC accuracy.
4. Based on characterization, not tested in production.
Figure 31. ADC accuracy characteristics
VREF+
VDDA
4096
[1LSBIDEAL
=
(or
depending on package)]
4096
EG
(1) Example of an actual transfer curve
(2) The ideal transfer curve
4095
4094
4093
(3) End point correlation line
(2)
ET=Total Unadjusted Error: maximum deviation
ET
between the actual and the ideal transfer curves.
(3)
7
6
5
4
3
2
1
EO=Offset Error: deviation between the first actual
transition and the first ideal one.
(1)
EG=Gain Error: deviation between the last ideal
transition and the last actual one.
EO
EL
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.
ED
1 LSBIDEAL
0
1
2
3
4
5
6
7
4093 4094 4095 4096
VDDA
VSSA
ai14395b
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Doc ID 13587 Rev 11
STMICROELECTRONICS [ ST ]
