Battery Backup; Voltage Regulator; Power Supply Schemes - ST STM32F10 Series Application Note

AN2586 - Application note
On packages with 64 pins or less
The V
REF+
voltage supply (V
1.1.2

Battery backup

To retain the content of the Backup registers when V
connected to an optional standby voltage supplied by a battery or another source.
The V
BAT
digital supply (V
down reset (PDR) circuitry embedded in the Reset block.
If no external battery is used in the application, V
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
Caution:
–
–
The V
100 nF ceramic capacitor + one Tantalum capacitor (min. 4.7 µF typ.10 µF).
The V
external battery is used, this pin must be connected to V
ceramic stabilization capacitor.
The V
ceramic + 1 µF Tantalum).
The V
external reference voltage is applied on V
connected on this pin. In all cases, V
and V pins are not available, they are internally connected to the ADC
REF-
) and ground (V
DDA
pin also powers the RTC unit, allowing the RTC to operate even when the main
) is turned off. The switch to the V
DD
If the ADC is used, the V
If the ADC is not used, the V
pins must be connected to V
DD
pin must be connected to the external battery (1.8 V < V
BAT
pin must be connected to two external stabilization capacitors (10 nF
DDA
pin can be connected to the V
REF+
).
SSA
is turned off, the V
DD
BAT
must be connected externally to V
BAT
.
DD
range is limited to 2.4 V to 3.6 V
DD
range is 2 V to 3.6 V
DD
with external stabilization capacitors (five
DD
external power supply. If a separate,
DDA
, two 10 nF and 1 µF capacitors must be
REF+
must be kept between 2.0 V and V
REF+
Power supplies
BAT
supply is controlled by the power
< 3.6 V). if no
BAT
with a 100 nF external
DD
pin can be
.
DD
.
DDA
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