If the design includes the use of external voltage references for analog modules, like the Analog-to-Digital Converter (ADC), the general recommendation is to use a suitable capacitor connected in parallel with the reference. The value of the capacitor depends on the nature of the reference and the type of electrical noise that needs to be filtered out.
Some references will also need additional filtering components. It is beyond the scope of these Hardware Guidelines to describe possible reference sources and their suggested filtering components, but in many cases, this will be described in the External Voltage Reference data sheet.
Figure 1. Recommended External Voltage
Reference Connection
