58.2.2 Power Supply Connections

The following figures shows the recommended power supply connections for switched/linear mode, linear mode only and with battery backup.

Figure 58-1. Power Supply Connection for Switching/Linear Mode
Figure 58-2. Power Supply Connection for Linear Mode Only
Figure 58-3. Power Supply Connection for Battery Backup Mode
Table 58-1. Power Supply Connections (1,2)
Signal Name Associated Ground Recommended Pin Connection
VDD VSS Capacitors: refer to REG_5
AVDD AVSS Capacitors: refer to REG_17

Ferrite Bead (3): Refer to REG_23/REG_25

VDDCORE VSS Capacitors: refer to REG_1
VSW - BUCK mode: Inductor required to VDDCORE: refer to REG_27/REG_29/REG_31

LDO mode: Not Connected
VBAT (PB03) VSS Capacitors: refer to REG_13
Note:
  1. REG_X values: refer to Power Supply Electrical Specifications from the Electrical Characteristics chapter.
  2. Decoupling capacitors must be placed close to the device, low ESR capacitors must be used for better decoupling.
  3. A ferrite bead must be added between the main power supply (VDD) and AVDD to attenuate high-frequency digital noise from entering the analog power domain. The bead must provide enough impedance to help isolate digital and analog power domains. Make sure to select a ferrite bead with a low DC resistance to avoid any relevant IR drop across the ferrite bead that could impact analog peripherals performance.