8 Reference design
8.1 Description
The reference designs shown in the next sections are based on STM32U5 devices in LQFP144 and TFBGA216
packages. This reference design can be tailored to any STM32U5 device with a different package, using the pin
correspondence given in Section 8.2 and Design reference for a STM32U599/5A9/5F9/5G9 device (with SMPS).
Clock
Two clock sources are used for the MCU (see Section 4 for more details):
• LSE: X1 – 32.768 kHz crystal for the embedded RTC
• HSE: X2 – 16 MHz crystal for the MCU
See Section 4 for more details.
Reset
The reset signal is active low in the reference design figures shown in Section 8.2.
The reset sources include:
• the reset button (B1)
• debugging tools via the connector CN1
See Section 2.4 for more details.
Boot mode
The user can add a switch on the board to change the boot option.
See Section 5 for more details.
Note: When waking up from Standby mode, the BOOT pin is sampled and the user must pay attention to its value.
SWD interface
The reference design shows the connection between the STM32U575/585 device and a standard SWD
connector.
See Section 6 for more details.
Note: To allow tools to reset the applications, the RESET pins must be connected.
Power supply
See Section 2 for more details.
AN5373
Reference design
AN5373 - Rev 6
page 36/47