7.1 Reference Voltages
Some analog peripherals require a reference voltage for proper operation.
Apart from external voltages (that is, VDDANA or
VREFx), the device has a DETREF module that provides two different internal
voltage references:
- BANDGAP: A stable voltage reference, fixed at 1.1V.
- INTREF: A variable voltage reference, configured by the Voltage References System Control register in the Supply Controller (SUPC.VREF).
The respective reference voltage source must be selected within each
dedicated analog peripheral register:
- ADC: Reference Control register (ADC.REFCTRL)
- DAC: Reference Selection bits in the Control B
register (DAC.CTRLB.REFSEL)Note: AC has a fixed reference voltage to BANDGAP value.