Datasheet

42. Schematic Checklist

42.1 Introduction

This chapter describes a common checklist which should be used when starting and reviewing the

schematics for a SAM D21 design. This chapter illustrates a recommended power supply connection,

how to connect external analog references, programmer, debugger, oscillator and crystal.

42.1.1 Operation in Noisy Environment

If the device is operating in an environment with much electromagnetic noise, it must be protected from

this noise to ensure reliable operation. In addition to following best practice EMC design guidelines, the

recommendations listed in the schematic checklist sections must be followed. In particular, placing

decoupling capacitors very close to the power pins, an RC-filter on the RESET pin, and a pull-up resistor

on the SWCLK pin is critical for reliable operations. It is also relevant to eliminate or attenuate noise in

order to avoid that it reaches supply pins, I/O pins and crystals.

42.2 Power Supply

The SAM D21 supports a single power supply from 1.62V - 3.63V.

42.2.1 Power Supply Connections

Figure 42-1. Power Supply Schematic

(1)

VDDANA

GNDANA

VDDIN

VDDIO

VDDCORE

GND

100nF

1.62V-3.63V

10µF

100nF10µF

Close to device

(for every pin)

1µF

Note: 1. It is recommended to use a ceramic or solid tantalum capacitor with low ESR. Refer to table

37-18 in 37.11.1 Voltage Regulator Characteristics for additional details on ESR.

SAM D21 Family

Schematic Checklist

Datasheet Complete

DS40001882D-page 1163