8.3 Reference Voltages

Some analog peripherals require a reference voltage for proper operation. Aside from external voltages (i.e., VDDANA), the device provides has a DETREF module that provides two internal voltage references:
  • BANDGAP: a stable voltage reference, refer to the Electrical Characteristics
  • INTREF: a variable voltage reference, configured by the Voltage References System Control register in the Supply Controller (SUPC.VREF)
The respective reference voltage source may be selected within the peripheral's registers:
  • ADC: Reference Control register (ADC.REFCTRL)
  • AC: Fixed to BANDGAP
  • DAC: Reference Selection bits in the Control B register (DAC.CTRLB.REFSEL)