STM32U5A5QJ datasheet(36/382 Pages) STMICROELECTRONICS

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Functional overview

STM32U5Axxx

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DS13543 Rev 1

backup registers (through power switch) when VDD is not present.

•

VDDDSI = 1.71 V to 3.6 V

VDDDSI is the external power supply for the DSI controller. It is provided externally

through VDDDSI supply pin, and must be connected to the same supply as VDD pin.

•

VDD11DSI = 1.0V to 1.26 V

VDD11DSI is the external power supply for the DSI transceiver and must be connected to

VDD11.

•

VREF-, VREF+

VREF+ is the input reference voltage for ADCs and DACs. It is also the output of the

internal voltage reference buffer when enabled.

VREF+ can be grounded when ADC and DAC are not active.

The internal voltage reference buffer supports four outputs:

–VREF+ around 1.5 V. This requires VDDA ≥ 1.8 V.

–VREF+ around 1.8 V. This requires VDDA ≥ 2.1 V.

–VREF+ around 2.048 V. This requires VDDA ≥ 2.4 V.

–VREF+ around 2.5 V. This requires VDDA ≥ 2.8 V.

VREF- and VREF+ pins are not available on all packages. When not available, they are

bonded to VSSA and VDDA, respectively.

When the VREF+ is double-bonded with VDDA in a package, the internal voltage

reference buffer is not available and must be kept disabled.

VREF- must always be equal to VSSA.

The STM32U5Axxx devices embed two regulators: one LDO and one SMPS in parallel to

provide the VCORE supply for digital peripherals, SRAM1, SRAM2, SRAM3, SRAM4,

SRAM5 and embedded flash memory. The SMPS generates this voltage on VDD11 (two or

three pins) with a total external capacitor of 4.7 μF typical. SMPS requires an external coil of

2.2 μH typical. The LDO generates this voltage on VCAP (one or two) pin(s) with a total

external capacitor of 4.7 μF typical.

Both regulators can provide four different voltages (voltage scaling) and can operate in

Stop modes. It is possible to switch from SMPS to LDO and from LDO to SMPS on-the-fly

(refer to the product reference manual for more details).

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