Datasheet

DocID023353 Rev 7 19/133
STM32F303xB STM32F303xC Functional overview
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3.12 Fast analog-to-digital converter (ADC)
Four fast analog-to-digital converters 5 MSPS, with selectable resolution between 12 and 6
bit, are embedded in the STM32F303xB/STM32F303xC family devices. The ADCs have up
to 39 external channels . Some of the external channels are shared between ADC1&2 and
between ADC3&4. The ADCs can perform conversions in single-shot or scan modes. In
scan mode, automatic conversion is performed on a selected group of analog inputs.
The ADCs have also internal channels: Temperature sensor connected to ADC1 channel
16, V
BAT/2
connected to ADC1 channel 17, Voltage reference V
REFINT
connected to the 4
ADCs channel 18, VREFOPAMP1 connected to ADC1 channel 15, VREFOPAMP2
connected to ADC2 channel 17, VREFOPAMP3 connected to ADC3 channel 17 and
VREFOPAMP4 connected to ADC4 channel 17.
Additional logic functions embedded in the ADC interface allow:
 Simultaneous sample and hold
 Interleaved sample and hold
 Single-shunt phase current reading techniques.
The ADC can be served by the DMA controller.
An analog watchdog feature allows very precise monitoring of the converted voltage of one,
some or all selected channels. An interrupt is generated when the converted voltage is
outside the programmed thresholds.
The events generated by the general-purpose timers and the advanced-control timers
(TIM1 and TIM8) can be internally connected to the ADC start trigger and injection trigger,
respectively, to allow the application to synchronize A/D conversion and timers.
3.12.1 Temperature sensor
The temperature sensor (TS) generates a voltage V
SENSE
that varies linearly with
temperature.
The temperature sensor is internally connected to the ADC1_IN16 input channel which is
used to convert the sensor output voltage into a digital value.
The sensor provides good linearity but it has to be calibrated to obtain good overall
accuracy of the temperature measurement. As the offset of the temperature sensor varies
from chip to chip due to process variation, the uncalibrated internal temperature sensor is
suitable for applications that detect temperature changes only.
To improve the accuracy of the temperature sensor measurement, each device is
individually factory-calibrated by ST. The temperature sensor factory calibration data are
stored by ST in the system memory area, accessible in read-only mode.
3.12.2 Internal voltage reference (V
REFINT
)
The internal voltage reference (V
REFINT
) provides a stable (bandgap) voltage output for the
ADC and Comparators. V
REFINT
is internally connected to the ADCx_IN18, x=1...4 input
channel. The precise voltage of V
REFINT
is individually measured for each part by ST during
production test and stored in the system memory area. It is accessible in read-only mode.