Datasheet

DocID025083 Rev 7 21/121
STM32F303x6/x8 Functional overview
44
3.10.2 Internal voltage reference (VREFINT)
The internal voltage reference (VREFINT) provides a stable (bandgap) voltage output for the
ADC and Comparators. V
REFINT is internally connected to the ADC1_IN18 and ADC2_IN18
input channels. 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.
3.10.3 V
BAT
battery voltage monitoring
This embedded hardware feature allows the application to measure the V
BAT
battery voltage
using the internal ADC channel ADC1_IN17. As the V
BAT
voltage may be higher than V
DDA
,
and thus outside the ADC input range, the V
BAT
pin is internally connected to a bridge
divider by 2. As a consequence, the converted digital value is half the V
BAT
voltage.
3.10.4 OPAMP2 reference voltage (VOPAMP2)
OPAMP2 reference voltage can be measured using ADC2 internal channel 17.
3.11 Digital-to-analog converter (DAC)
One 12-bit buffered DAC channel (DAC1_OUT1) and two 12-bit unbuffered DAC channels
(DAC1_OUT2 and DAC2_OUT1) can be used to convert digital signals into analog voltage
signal outputs. The chosen design structure is composed of integrated resistor strings and
an amplifier in inverting configuration.
This digital interface supports the following features:
• Three DAC output channels
• 8-bit or 12-bit monotonic output
• Left or right data alignment in 12-bit mode
• Synchronized update capability
• Noise-wave generation (only on DAC1)
• Triangular-wave generation (only on DAC1)
• Dual DAC channel independent or simultaneous conversions
• DMA capability for each channel
• External triggers for conversion
3.12 Operational amplifier (OPAMP)
The STM32F303x6/8 embeds an operational amplifier (OPAMP2) with external or internal
follower routing and PGA capability (or even amplifier and filter capability with external
components). When an operational amplifier is selected, an external ADC channel is used
to enable output measurement.
The operational amplifier features:
• 8 MHz GBP
• 0.5 mA output capability
• Rail-to-rail input/output
• In PGA mode, the gain can be programmed to 2, 4, 8 or 16.
Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.