Calculating the actual VDDA voltage using the internal reference voltage
The VDDA power supply voltage applied to the microcontroller may be subject to variation or
not precisely known. The embedded internal voltage reference (VREFINT) and its calibration
data acquired by the ADC during the manufacturing process at VDDA = 3.3 V can be used to
evaluate the actual VDDA voltage level.
The following formula gives the actual VDDA voltage supplying the device:
VDDA = 3.3 V ₓ VREFINT_CAL / VREFINT_DATA
Where:
• VREFINT_CAL is the VREFINT calibration value
• VREFINT_DATA is the actual VREFINT output value converted by ADC