45.2.1 Power Supply Connections

Note: 1. It is recommended to use a ceramic or solid tantalum capacitor with low ESR. Refer to table 37-18 in Voltage Regulator Characteristics for additional details on ESR.

Table 45-1. Power Supply Connections, V_DDCORE From Internal Regulator
Signal Name	Recommended Pin Connection	Description
V_DDIO	1.62V - 3.63V Decoupling/filtering capacitors 100nF⁽¹⁾⁽²⁾ and 10μF⁽¹⁾ Decoupling/filtering inductor 10μH⁽¹⁾⁽³⁾	Digital supply voltage
V_DDANA	1.62V - 3.63V Decoupling/filtering capacitors 100nF⁽¹⁾⁽²⁾ and 10μF⁽¹⁾ Ferrite bead⁽⁴⁾ prevents the V_DD noise interfering the V_DDANA	Analog supply voltage
V_DDCORE	1.6V to 1.8V  Decoupling/filtering capacitor 1μF⁽¹⁾⁽²⁾	Core supply voltage / external decoupling pin
GND		Ground
GND_ANA		Ground for the analog power domain

Note:

These values are only given as typical examples.
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.
An inductor should be added between the external power and the V_DD for power filtering.
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. 50Ω 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.

SAM D21/DA1 Family

45.2.1 Power Supply Connections