2 Overview

The DAC supplies a variable voltage reference that is ratiometric with the input source and has 32 selectable output levels.

Figure 2-1. Block Diagram of DAC
The 5-bit DAC features include:
  • Flexible input source (both positive and negative)
  • Selection of the DAC output, as a reference to the following internal peripherals:
    • DACxOUT1 pin
    • DACxOUT2 pin
    • Comparator positive input
    • ADC input channel

The flexible input reference voltage (both positive input source (Vsource+) and negative input source (Vsource-)) aids in configuring a range of reference voltages from negative (-) to positive (+).

The positive input source of the DAC can be connected to three sources:
  • FVR Buffer
  • External VREF+ Pin
  • VDD supply voltage

The Fixed Voltage Reference (FVR) is an internal module providing stable voltage references; Table 4-5 showcases those levels of voltages, which are limited to less than the VDD voltage. An external VREF+ pin is used when the user wishes to provide the input from an external source.

The VDD supply voltage of the microcontroller can also be used as a voltage resource to the positive input source of the DAC. The negative input source (Vsource-) of the DAC can be connected to the two sources:

  • External VREF- Pin
  • VSS

The external VREF- pin is a negative reference voltage pin, which can be used when the user wishes to provide the input from an external voltage source. (Refer to Electric Characteristics in the device-specific data sheet).

The VSS supply voltage pin is an operating supply ground (GND) pin, which can be used as a negative input source to the DAC. The output of DAC can be routed to other peripherals as a reference voltage. This includes:

  • Noninverting input of comparator
  • ADC input channel
  • Microcontroller pins: DACxOUT1 and DACxOUT2

This feature makes DAC a flexible module suitable for a wide range of applications.