Datasheet

59. Schematic Checklist
59.1 Introduction
This chapter describes a common checklist which should be used when starting and reviewing the
schematics for a SAM D5x/E5x design. This chapter illustrates recommended power supply connections,
how to connect external analog references, programmer, debugger, oscillator and crystal.
59.1.1 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.
59.2 Power Supply
The SAM D5x/E5x supports a single or dual power supply from 1.71V to 3.63V. The same voltage must
be applied to both VDDIO and VDDANA. VDDIOB level must be lower or equal to VDDIO / VDDANA.
When I/O pads in the VDDIOB cluster are multiplexed as analog pads, VDDANA is used to power the I/O.
Using this configuration may result in an electrical conflict if the VDDIOB voltage is different from that of
VDDIO / VDDANA. If the application has such requirements, it is required to power VDDIOB, VDDIO, and
VDDANA from the same supply source to ensure that they are always at the same voltage.
The internal voltage regulator has four different modes:
• Linear mode: This mode does not require any external inductor. This is the default mode when CPU
and peripherals are running
• Switching mode (Buck): The most efficient mode when the CPU and peripherals are running.
• Low Power (LP) mode: This is the default mode used when the device is in Standby mode
• Shutdown mode: When the device is in Backup mode, the internal regulator is turned off
Selecting between switching mode and linear mode can be done by software on the fly, but the power
supply must be designed according to which mode is to be used.
59.2.1 Power Supply Connections
The following figures shows the recommended power supply connections for switched/linear mode, linear
mode only and with battery backup.
SAM D5x/E5x Family Data Sheet
Schematic Checklist
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 2096