36.2.1 Power Supply Connections

Figure 36-1. Power Supply Schematic (1)
Note:
  1. VDDANA and VDDIO were shorted during characterization and a Ferrite bead was not used.
  2. Not all capacitors are required. Refer to electrical characteristics tables 32.17 and 34.15 to know which capacitors are mandatory and their values.
Table 36-1. Power Supply Connections, VDDCORE From Internal Regulator
Signal NameRecommended Pin ConnectionDescription
VDDIO1.62V - 3.63V

Decoupling/filtering capacitors 100nF(1)(2) and 10μF(1)

Decoupling/filtering inductor 10μH(1)(3)

Digital supply voltage
VDDIN1.62V - 3.63V

Decoupling/filtering capacitors:

cf electrical characteristics tables 32.17 and 34.15 to know which capacitors are mandatory and their values.
Core supply voltage
VDDANA1.62V - 3.63V

Decoupling/filtering capacitors 100nF(1)(2) and 10μF(1)

Ferrite bead(4) prevents the VDD noise interfering the VDDANA

Analog supply voltage
VDDCORE1.6V to 1.8V
 Decoupling/filtering capacitor 1μF(1)(2)Core supply voltage / external decoupling pin
GNDGround
GNDANAGround for the analog power domain
Note:
  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 VDD for power filtering.
  4. Ferrite bead has better filtering performance than the common inductor at high frequencies. It can be added between VDD and VDDANA 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.