STM32L412 - WLCSP64 IC - USB configuration

[BR.3]

Hi All,

Iam using this STM32L412 MCU based WIFI module (Murata's Type 1LD module) in my project. Currently powering it with 1.8VDC for the operation and my other peripheral are 1.8V logic also it is battery operated project . Here im not able to bring it up the USB interface. Is it because of this 1.8V power ?

(Datasheet link for murata module : https://wireless.murata.com/type-1ld-ayla.html )

After referring the STM32 MCU datasheet i could see VDD should be at-least 2.7V min or 3.3V nominal for the USB operation. There is no dedicated VDD_USB for this 64 pin MCU. In that case if VDDA & VBAT_MCU is powered with 3.3V and VDDIO with 1.8V then will this USB section will start work ?

Whether VDDA and VUSB is enough for the internal USB phy to start functioning ?

I know this is not STM part but still looking for some basic info related to the MCU.

Please advise.

[TDK]

> WLCSP64

Do you mean WLCSP36?

 

Since VDDUSB isn't broken out to a pin, it is tied to VDD internally. Per the datasheet, you need 2.7V min for USB operation, and 3.0V min for USB compliance.

The VDDUSB pin is present on 64-pin packages.

https://www.st.com/resource/en/application_note/dm00296349-usb-hardware-and-pcb-guidelines-using-stm32-mcus-stmicroelectronics.pdf

[BR.3]

Hi,

Sorry Typo mistake. The MCU is STM32F412. I referred your app note and i got your valid point. This WLCSP64 dosent have dedicated VDD_USB. I hope it uses VDD as a reference for internal USB blocks. Please correct me if im wrong.

[TDK]

If the VDDUSB pin is not present, it is internally tied to VDD.