40.4 External Analog Reference Connections

The following schematic checklist is only required if the application is using the external analog reference. For unused VREFx inputs, the following circuit is not necessary.

Figure 40-4. External Analog Reference Schematic With One Reference
Table 40-1. External Analog Reference Connections
Signal NameRecommended Pin ConnectionDescription
VREFx2.4V to VDDANA - 0.6V for ADC (2)

2.4V to VDDANA - 0.6V for DAC (2)

Decoupling/filtering capacitors: 100 nF(1,2,3) and 4.7 µF(1)

External reference from the VREFx pin on the analog port
GNDGround
Note:
  1. Refer to the Power Supply Electrical Specifications in the Electrical Characteristics chapter.
  2. Refer to the Electrical Characteristics chapter for the intended peripheral to be used with VREFx to determine the suggested operational conditions. Examples are peripherals such as the ADC, DAC, AC, and SDADC.
  3. A decoupling capacitor must be placed close to the device for each supply pin pair in the signal group.