ST STM32F10 Series, Примечание к применению

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AN2586 - Application note Power supplies
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On packages with 64 pins or less
The V
REF+
and V
REF-
pins are not available, they are internally connected to the ADC
voltage supply (V
DDA
) and ground (V
SSA
).
1.1.2 Battery backup
To retain the content of the Backup registers when V
DD
is turned off, the V
BAT
pin can be
connected to an optional standby voltage supplied by a battery or another source.
The V
BAT
pin also powers the RTC unit, allowing the RTC to operate even when the main
digital supply (V
DD
) is turned off. The switch to the V
BAT
supply is controlled by the power
down reset (PDR) circuitry embedded in the Reset block.
If no external battery is used in the application, V
BAT
must be connected externally to V
DD
.
1.1.3 Voltage regulator
The voltage regulator is always enabled after reset. It works in three different modes
depending on the application modes.
●
in Run mode, the regulator supplies full power to the 1.8 V domain (core, memories and
digital peripherals)
●
in Stop mode, the regulator supplies low power to the 1.8 V domain, preserving the
contents of the registers and SRAM
●
in Standby mode, the regulator is powered off. The contents of the registers and SRAM
are lost except for those concerned with the Standby circuitry and the Backup domain.
1.2 Power supply schemes
The circuit is powered by a stabilized power supply, V
DD
.
●
Caution:
– If the ADC is used, the V
DD
range is limited to 2.4 V to 3.6 V
– If the ADC is not used, the V
DD
range is 2 V to 3.6 V
●
The V
DD
pins must be connected to V
DD
with external stabilization capacitors (five
100 nF ceramic cap one Tantalum capacitor (min. 4.7 µF typ.10 µF).
●
The V
BAT
pin must be connected to the external battery (1.8 V < V
BAT
< 3.6 V). if no
external battery is used, this pin must be connected to V
DD
with a 100 nF external
ceramic stabilization capacitor.
●
The V
DDA
pin must be connected to two external stabilization capacitors (10 nF
c 1 µF Tantalum).
●
The V
REF+
pin can be connected to the V
DDA
external power supply. If a separate,
external reference voltage is applied on V
REF+
, two 10 nF and 1 µF capacitors must be
connected on this pin. In all cases, V
REF+
must be kept between 2.0 V and V
DDA
.