Figure 23. Adc Accuracy Characteristics; Figure 24. Typical Connection Diagram Using The Adc - STMicroelectronics STM32F050G6 Manual

STM32F050xx
2. 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 I
affect the ADC accuracy.
3. Better performance may be achieved in restricted V
4. Data based on characterization results, not tested in production.

Figure 23. ADC accuracy characteristics

1 LSB
IDEAL
4095
4094
4093
7
6
5
E
O
4
3
2
1
0
1 2 3
V
SSA

Figure 24. Typical connection diagram using the ADC

V AIN
1. Refer to
2. C
parasitic
pad capacitance (roughly 7 pF). A high C
this, f
ADC
General PCB design guidelines
Power supply decoupling should be performed as shown in
should be ceramic (good quality) and it should be placed as close as possible to the chip.
V
DDA
4096
(2)
E
T
E
L
E
D
1 LSB
IDEAL
4 5 6 7
R AIN (1)
AINx
C parasitic
Table 49 for the values of R
represents the capacitance of the PCB (dependent on soldering and PCB layout quality) plus the
should be reduced.
Doc ID 023079 Rev 3
INJ(PIN)
, frequency and temperature ranges.
DDA
E
G
(1) Example of an actual transfer curve
(2) The ideal transfer curve
(3) End point correlation line
=Total Unadjusted Error: maximum deviation
between the actual and the ideal transfer curves.
(3)
=Offset Error: deviation between the first actual
transition and the first ideal one.
(1)
=Gain Error: deviation between the last ideal
transition and the last actual one.
=Differential Linearity Error: maximum deviation
between actual steps and the ideal one.
=Integral Linearity Error: maximum deviation
between any actual transition and the end point
correlation line.
4093 4094 4095 4096
V
DDA
V DDA
V T
0.6 V
I L ±1 μA
V T
0.6 V
, R and C .
AIN ADC ADC
value will downgrade conversion accuracy. To remedy
parasitic
Electrical characteristics
and I
in Section 6.3.13
INJ(PIN)
Sample and hold ADC
converter
R ADC
12-bit
converter
C ADC
Figure 11. The 10 nF capacitor
does not
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MS19881V2
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