Mcu Power Supply; Table 9. Mcu Power Supplies - ST STM32U5 User Manual

6.4.4.2 1V8
An external SMPS can be used for the MCU to work at 1.8 V. The external SMPS capability is 400mA maximum.
Before using the 1.8 V voltage, it is necessary to check that all interfaces connected to the Nucleo-144 board are
1.8 V compatible. To select the 1.8 V for the VDD, set the VDD jumper (JP4) on [2-3].
In this mode, it is possible to keep some MCU voltage domain at 3V3 depending on the application use case.
The MCU voltage selection is done according to the solder bridge configuration. Refer to
configuration.
6.4.4.3 JP4 VDD voltage selection 1V8/3V3
The JP4 jumper selects the VDD voltage:
• Set JP4 on [1-2] to set VDD to 3V3.
• Set JP4 on [2-3] to set VDD to 1V8.
The consumption on this jumper includes the MCU power pins connected to the VDD_MCU power line and the
other features supplied by VDD, such as the level shifter power supply pins for STLINK-V3E, the user button, the
®
ARDUINO shield on the IOREF pin, and power supply pins on the ST morpho connector.
6.4.5

MCU power supply

The default configuration of the MCU power pins is described in
Solder bridge
configuration
JP4 [1-2] / JP4 [2-3]
JP5 [1-2] / ammeter
SB2 ON
SB3 ON
SB30 ON
SB28 ON / SB29 OFF
SB50 ON
SB55 OFF / SB54 ON
Warning:
INTERNAL VCORE SMPS power supply
Power figures in run mode are significantly improved, by generating a V
converter (this function is only available on '-Q' suffixed boards).
For all general information concerning design recommendations for STM32U5 with internal SMPS and design
guide for ultra‑low‑power applications with performance, refer to the application note Getting started with
STM32U575/585 MCU hardware development (AN5373) at the
UM2861 - Rev 5
Table 9.
VDD selection: Jumper selection for VDD 3V3 / 1V8
I : JP5 ON to supply the MCU or connected with an ammeter to do the current measurement.
DD
SB for VDDSMPS input voltage
SB for VREFP input voltage
SB for VDDUSB input voltage
SB for VDDIO2 PG[2-15] input voltage
SB28 ON / SB29 OFF: VDDIO follows 1V8 to 3V3 VDD_MCU.
SB28 OFF / SB29 ON: VDDIO fixed to 3V3 whatever the VDD-MCU voltage is.
SB for VBAT input voltage
SB for VDDA/VREF input voltage
SB55 ON / SB54 OFF: VDDA/VREF follows 1V8 to 3V3 VDD_MCU.
SB55 OFF / SB54 ON: VDDA/VREF fixed to 3V3 whatever the VDD-MCU voltage is.
For more detail about VDDA/VREFP power supply, refer to the MCU datasheet.
On this Nucleo-144, the power
given as an example and might not follow the recommended power
to the application note Getting started with STM32U575/585 MCU hardware development
(AN5373) and STM32U5xx products datasheets for power on sequencing.
Table 9.
MCU power supplies
MCU power supply
‑ on sequence implementation for the 1.8 V use case is
logic supply from the internal DC/DC
core
www.st.com website.
UM2861
Power supply and power selection
Table 9 for solder bridge
‑ on sequencing. Refer
page 23/49