STM32L4+ power scheme design while working at 1.8v

[Moamen Ayman]

Hello, I will use STM32L4R9AI in a battery powered design with PSRAM that powered at 1.8v and flash memory that can work at wider voltage range (in addition to DSI display, RTC, ADC, DAC, USB, I2C) so my power scheme is as following:

MCU:

VDD : 1.8v

VDDIO2: 1.8v

VDDDSI: 1.8V

VBAT: 1.8v (regulated and sourced directly from the battery)

VDDA and Vref+: 3.3v

VUSB: 3.3v

-------------------------------------

PSRAM:

VCC: 1.8v

VCCQ: 1.8V

------------------------------------

Flash:

VCCQ: 1.8v

VCC: 3.3v

------------------------------------

OLED display:

VDDIO: 1.8v

VDD: 3.3v

---------------------------------

I attached the datasheet for the PSRAM, Nand flash and Display.

I have 3 questions:

1- is this power design correct and MCU is expected to work with other modules?

2- I will use external STLink v2 programmer (like the one in the attached photo) to flash and debug the firmware on the motherboard through SWD which will be connected through reserved pins on the PCB, but STLink works at 3.3v and here the MCU I/Os work at 1.8v so will that cause problem, if there is a problem what do you suggest?

3- Finally I will connect a sensor works at 3.3v (doesn't support 1.8v) through I2C to the MCU, can I connect it directly to the MCU or I have to use level translator (3.3v to 1.8v)?

Thanks in Advance!