Power Supply Schemes - ST STM32F4 Series Application Note

AN4488
2.2

Power supply schemes

The circuit is powered by a stabilized power supply, V
Caution: The V
DD
Datasheet for details).
•
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
be connected on this pin. In all cases, V
V
DDA
•
Additional precautions can be taken to filter analog noise:
–
–
•
For the voltage regulator configuration, there is specific BYPASS_REG pin (not
available on all packages) that should be connected either to V
deactivate the voltage regulator specific.
–
• When the voltage regulator is enabled, V
2*2.2 µF LowESR < 2Ω Ceramic capacitor (or 1*4.7 µF LowESR < 1Ω Ceramic
capacitor if only V
voltage range is 1.8 V to 3.6 V (down to 1.7 V with some restrictions, see relative
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+
with minimum of 1.7 V.
V can be connected to V
DDA
The V pin can be connected to V
REF+
Refer to Section 2.1.2
datasheet for details.
pin is provided on some packages).
CAP1
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
REF+
must be kept between (V
REF+
through a ferrite bead.
DD
through a resistor.
DDA
and section "Voltage regulator" of the related device
and V
CAP1
AN4488 Rev 7
Power supplies
.
< 3.6 V). If no
BAT
with a 100 nF
DD
DDA
or V
SS DD
pins must be connected to
CAP2
-1.2 V) and
to activate or
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