Power Control (Pwr); Power Supplies - ST STM32L4x6 Reference Manual

RM0351
5

Power control (PWR)

5.1

Power supplies

The STM32L4x devices require a 1.71 V to 3.6 V V
independent supplies (V
peripherals:
•
V
DD
V
DD
analog such as reset, power management and internal clocks. It is provided externally
through VDD pins.
•
V
DDA
V
DDA
reference buffer, operational amplifiers and comparators. The V
independent from the V
these peripherals are not used.
•
V
DDUSB
V
DDUSB
voltage level is independent from the V
to V
• V
DDIO2
V
DDIO2
is independent from the V
PG[15:2] are not used.
•
V
LCD
The LCD controller can be powered either externally through VLCD pin, or internally
from an internal voltage generated by the embedded step-up converter. VLCD is
multiplexed with PC3 which can be used as GPIO when the LCD is not used.
•
V
BAT
V
BAT
(through power switch) when V
• V
REF-
V
REF+
internal voltage reference buffer when enabled.
When V
When V
V
REF+
The internal voltage reference buffer supports two output voltages, which are
configured with VRS bit in the VREFBUF_CSR register:
–
–
VREF- and VREF+ pins are not available on all packages. When not available, they are
bonded to VSSA and VDDA, respectively.
, V
DDA
= 1.71 V to 3.6 V
is the external power supply for the I/Os, the internal regulator and the system
= 1.62 V (ADCs/COMPs) / 1.8 V (DACs/OPAMPs) to 2.4 V (VREFBUF) to 3.6 V
is the external analog power supply for A/D converters, D/A converters, voltage
DD
= 3.0 V to 3.6 V
is the external independent power supply for USB transceivers. The V
when the USB is not used.
DD
= 1.08 V to 3.6 V
is the external power supply for 14 I/Os (Port G[15:2]). The V
= 2.5 V to 3.6 V
= 1.55 V to 3.6 V
is the power supply for RTC, external clock 32 kHz oscillator and backup registers
, V
REF+
is the input reference voltage for ADCs and DACs. It is also the output of the
< 2 V V must be equal to V
DDA REF+
≥ 2 V V must be between 2 V and V
DDA REF+
can be grounded when ADC and DAC are not active.
V around 2.048 V. This requires V
REF+
V around 2.5 V. This requires V
REF+
DocID024597 Rev 3
DD
, V , V ), can be provided for specific
DDIO2 DDUSB LCD
voltage and should preferably be connected to V
voltage and should preferably be connected
DD
voltage and should preferably be connected to V
DD
is not present.
DD
DDA
DDA
equal to or higher than 2.8 V.
DDA
Power control (PWR)
operating voltage supply. Several
voltage level is
DDA
DDIO2
.
.
DDA
equal to or higher than 2.4 V.
when
DD
DDUSB
voltage level
when
DD
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