Datasheet

STM32F405xx, STM32F407xx Electrical characteristics
Doc ID 022152 Rev 2 63/167
5.1.6 Power supply scheme
Figure 18. Power supply scheme
1. Each power supply pair must be decoupled with filtering ceramic capacitors as shown above. These capacitors must be
placed as close as possible to, or below, the appropriate pins on the underside of the PCB to ensure the good functionality
of the device.
2. To connect BYPASS_REG and PDR_ON pins, refer to Section 2.2.17: Real-time clock (RTC), backup SRAM and backup
registers.
3. The two 2.2 µF ceramic capacitors should not be connected when the voltage regulator is OFF.
4. The 4.7 µF ceramic capacitor must be connected to one of the V
DD
pin.
5. V
DDA
=V
DD
and V
SSA
=V
SS
.
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