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STM32F20xxx Electrical characteristics
177
6.1.6 Power supply scheme
Figure 19. 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 REGOFF and IRROFF pins, refer to Section 3.16: Voltage regulator.
3. The two 2.2 µF ceramic capacitors should be replaced by two 100 nF decoupling capacitors when the voltage regulator is
OFF.
4. The 4.7 µF ceramic capacitor must be connected to one of the V
DD
pin.
ai17527e
V
DD
1/2/...14/15
V
BAT
GP I/Os
OUT
IN
Kernel logic
(CPU,
digital
& RAM)
Backup circuitry
(OSC32K,RTC,
Backup registers,
backup RAM)
Wakeup logic
15 × 100 nF
+ 1 × 4.7 μF
1.8-3.6 V
V
SS
1/2/...14/15
V
DDA
V
REF+
V
REF-
V
SSA
ADC
Level shifter
IO
Logic
V
DD
100 nF
+ 1 μF
V
REF
100 nF
+ 1 μF
V
DD
Flash memory
V
CAP_1
V
CAP_2
2 × 2.2 μF
REGOFF
IRROFF
Power switch
Analog
RCs, PLL,
...
Voltage
regulator