Atmel Xplained Pro Evaluation Kit ATSAMD20-XPRO ATSAMD20-XPRO Data Sheet

609

Atmel | SMART SAM D20 [DATASHEET]

Atmel-42129K–SAM-D20_datasheet–06/2014

Notes:

1.

These values are only given as typical examples.

2.

Decoupling capacitor should be placed close to the device for each supply pin pair in the signal group, low 
ESR caps should be used for better decoupling.

3.

An inductor should be added between the external power and the V

DD

 for power filtering.

4.

Ferrite bead has better filtering performance than the common inductor at high frequencies. It can be added 
between V

DD

 and V

DDANA

 for preventing digital noise from entering the analog power domain. The bead 

should provide enough impedance (e.g. 50

Ω at 20MHz and 220Ω at 100MHz) for separating the digital 

power from the analog power domain. Make sure to select a ferrite bead designed for filtering applications 
with a low DC resistance to avoid a large voltage drop across the ferrite bead.

The following schematic checklist is only necessary if the application is using one or more of the external analog 
references. If the internal references are used instead, the following circuits in 

 and 

 are not 

necessary.

V

DDCORE

1.6V to 1.8V
Decoupling/filtering capacitor 100nF

Core supply voltage / external decoupling pin

GND

Ground

GND

ANA

Ground for the analog power domain

GND

AREFA

EXTERNAL

REFERENCE 1

4.7µF

100nF

GND

AREFB

EXTERNAL

REFERENCE 2

4.7µF

100nF

Close to device

(for every pin)