Figure 26. Adc Accuracy Characteristics; Figure 27. Typical Connection Diagram Using The Adc - STMicroelectronics STM32F042F4 Manual

STM32F042x4 STM32F042x6
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
accuracy.
3. Better performance may be achieved in restricted V
4. Data based on characterization results, not tested in production.
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
scheme. The 10 nF capacitor should be ceramic (good quality) and it should be placed as
close as possible to the chip.

Figure 26. ADC accuracy characteristics

Figure 27. Typical connection diagram using the ADC

Table 54: ADC characteristics
represents the capacitance of the PCB (dependent on soldering and PCB layout quality) plus the
should be reduced.
DocID025832 Rev 5
and ΣI
INJ(PIN) INJ(PIN)
, frequency and temperature ranges.
DDA
for the values of R , R
AIN
value will downgrade conversion accuracy. To remedy
parasitic
Electrical characteristics
in does not affect the ADC
Section 6.3.14
and C .
ADC ADC
Figure 13: Power supply
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