ST STM32H74xI/G User Manual

AN4938 Rev 4 7/46
AN4938 General information
45
1 General information
This document applies to STM32H74xI/G and STM32H75xI/G Arm
®(a)
-based devices.
2 Power supplies
2.1 Introduction
STM32H74xI/G and STM32H75xI/G devices require a 1.71 to 3.6 V operating voltage
supply (V
DD
), which can be reduced down to 1.62 V by using an external power supervisor
and connecting PDR_ON pin to V
SS
(refer to the datasheets for details).
The digital power can be supplied either by a internal system supply voltage regulator or
di
rectly by an external supply voltage. This digital power voltage can be set dynamically at
different values, the highest value allowing to achieve the maximum performance.
The real-time clock (RTC), the RTC backup registers, and the backup SR
AM (BKP SRAM)
can be powered from the V
BAT
voltage (1.2 to 3.6 V) when the main V
DD
supply is powered
OFF.
Note: Refer to the product datasheets for more details on the supply voltage range.
2.1.1 Independent analog supply and reference voltage
To improve analog peripheral performance, the analog peripherals feature an independent
power supply which can be separately filtered and shielded from noise on the PCB:
• The analog supply voltage input is available on a separate VDDA pin.
• An isolated supply ground connection is p
rovided on the pin V
SSA
.
To ensure a better accuracy of low-voltage inputs, the user can connect a separate external
refe
rence voltage on V
REF+
.
In addition, the STM32H74xI/G and STM32H75xI/G microcon
trollers embed an internal
voltage reference buffer, which can be used as voltage reference for ADCs, DACs, as well
as external components through the V
REF+
pin. This buffer supports four voltages that can
be configured through the VREFBUF_CSR register.
When available (depending on the package), V
REF–
pin must be externally tied to V
SSA
.
V
DDA
minimum value (V
DDA_MIN
) depends on the analog peripheral and on whether a
reference voltage is provided or not:
• If no analog peripheral is used, V
DDAmin
equals 0 V.
• When an ADC or a comparator is used, V
DDA_MIN
equals 1.62 V.
• When a DAC is used, V
DDA_MIN
equals 1.8V.
a. Arm is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere.

ST STM32H74xI/G Specifications

General

Brand	ST
Model	STM32H74xI/G
Category	Microcontrollers
Language	English