Temperature-Effect Compensation; Minimizing Injection Current; Minimizing I/O Pin Crosstalk - ST STM32 Application Note

AN2834
3.2.8

Temperature-effect compensation

One method is be to fully characterize the offset and gain drift and provide a lookup table in
memory to correct measurement according to temperature change. This calibration involves
additional cost and takes time.
The second method consists in recalibrating the ADC when the temperature change
reaches given values, by using the internal temperature sensor and the ADC watchdog.
3.2.9

Minimizing injection current

Check the application to verify whether any digital or analog input voltage can be less than
V or V
SS
on the accuracy will be greater if a digital input is close to the analog input being converted.
Negative current injection on any of the standard (non-robust) analog input pins should be
avoided as this would significantly reduce the accuracy of the conversion being performed
on another analog input.
It is recommended to connect a Schottky diode between V
birth to the negative injection current.
The ADC accuracy will not be affected by positive injection currents within the limits
specified for I
characteristics section).
3.2.10

Minimizing I/O pin crosstalk

The noise produced by crosstalk can be reduced by shielding the analog signal by placing
ground tracks across it.
. If it is the case, a negative injection current will flow from the pins. The effect
SSA
and ΣI
INJ(PIN) INJ(PIN)
Figure 27
Figure 27. Crosstalk between I/O pins
(refer to the appropriate STM32 datasheet, I/O port
shows the recommended grounding between signals.
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SSA
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