Power Supply Schemes - ST STM32F20 Series Application Note

Power supplies
1.2

Power supply schemes

The circuit is powered by a stabilized power supply, V
●
Caution:
–
● The V
single Tantalum or Ceramic capacitor (min. 4.7 µF typ.10 µF) for the package + one
100 nF Ceramic capacitor for each V
● The V
external battery is used, it is recommended to connect this pin to V
external ceramic decoupling capacitor.
●
The V
Ceramic + 1 µF Tantalum or Ceramic).
●
The V
external reference voltage is applied on V
connected on this pin. In all cases, V
●
Additional precautions can be taken to filter analog noise:
–
–
●
For the voltage regulator configuration, there are specific pins (REGOFF and IRROFF
depending on the package) that should be connected either to VSS or VDD to activate
or deactivate the voltage regulator specific. Refer to section "Voltage regulator" in
STM32F20xxx/21xxx datasheet for details.
●
When the voltage regulator is enabled, V
2*2.2 µF Ceramic capacitor.
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The V voltage range is 1.8 V to 3.6 V (and 1.65 V to 3.6 V for WLCSP64+2
DD
package)
pins must be connected to V
DD
pin can be connected to the external battery (1.65 V < V
BAT
pin must be connected to two external decoupling capacitors (100 nF
DDA
pin can be connected to the V
REF+
V can be connected to V
DDA
The V pin can be connected to V
REF+
Doc ID 18267 Rev 2
.
DD
with external decoupling capacitors: one
DD
pin.
DD
external power supply. If a separate,
DDA
, a 100 nF and a 1 µF capacitors must be
REF+
must be kept between 1.65 V and V
REF+
through a ferrite bead.
DD
through a resistor (typ. 47
DDA
and V
CAP1 CAP2
AN3320
< 3.6 V). If no
BAT
with a 100 nF
DD
DDA
Ω
).
pins must be connected to
.