Figure 20. Power Supply And Reference Decoupling For 100- And 144-Pin Packages; Figure 21. Power Supply Decoupling For 36-, 48- And 64-Pin Packages - ST STM32 Application Note

AN2834
To filter high-frequency noise, a ferrite inductance in series with the power supply can be
used. This solution leads to very low (negligible) DC loss unless the current is high because
the series resistance of the wire is very low. At high frequencies, however, the impedance is
high.
STM32 microcontroller side
In most STM32 microcontrollers, the V
are the V
microcontroller with very short leads. For multiple V
decoupling capacitors.
The V
DDA
1 µF Tantalum or Ceramic). Refer to
For STM32 microcontrollers delivered in 100/144-pin packages, it is possible to improve the
accuracy on low-voltage inputs by connecting a separate external ADC reference voltage
input on V
V . If a separate, external reference voltage is applied on V
DDA
capacitors must be connected on this pin. In all cases, V
and V
DDA

Figure 20. Power supply and reference decoupling for 100- and 144-pin packages

and V pins. A capacitor can therefore be connected very close to the
REF+ SSA
pin must be connected to two external decoupling capacitors (10 nF Ceramic +
(refer to Section
REF+
.

Figure 21. Power supply decoupling for 36-, 48- and 64-pin packages

and V pins are placed close to each other. So
DD SS
DD
Figure 20 and Figure 21
3.2.5). The voltage on V
DocID15067 Rev 3
How to get the best ADC accuracy
and V pins, use separate
SS
for decoupling examples.
may range from 2.4 V to
REF+
, two 10 nF and 1 µF
REF+
must be kept between 2.4 V
REF+
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