Functional overview
STM32F302xx/STM32F303xx
3.12
Fast analog-to-digital converter (ADC)
Up to four fast analog-to-digital converters 5 MSPS, with selectable resolution between 12
and 6 bit, are embedded in the STM32F302xx/STM32F303xx family devices. The ADCs
have up to 39 external channels. Some of the external channels are shared between
ADC1&2 and between ADC3&4, performing 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
connected to ADC1 channel 17, Voltage reference V
connected to the 4
BAT/2
REFINT
ADCs channel 18, VOPAMP1 connected to ADC1 channel 15, VOPAMP2 connected to
ADC2 channel 17, VOPAMP3 connected to ADC3 channel 17, VOPAMP4 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
on all devices and TIM8 on STM32F303xB/STM32F303xC devices) 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
temperature.
that varies linearly with
SENSE
The temperature sensor is internally connected to the ADC_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
) provides a stable (bandgap) voltage output for the
REFINT
ADC and Comparators. V
is internally connected to the ADC_IN18 input channel. The
REFINT
precise voltage of V
is individually measured for each part by ST during production
REFINT
test and stored in the system memory area. It is accessible in read-only mode.
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Doc ID 023353 Rev 5
STMICROELECTRONICS [ ST ]
