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Query on Class B library - STM32U585 MCU to meet IEC60730/UL1998 certification.


Hello team,


We have selected Trust zone MCU STM32U585ZIT6Q (U5 series) for our product (EV charger).

we have a query regarding the UL certification.

Based on the attached user guide snapshot, we could understand this U5 series chip have a Class B library that supports IEC 61518 and was adopted to fulfil the IEC60730 requirement.

But we understand that STM32U5 series is not in the list of MCU series (Pre certified) in UL certification for class B.

Is that ok to proceed with using this MCU in our product development and getting UL certification (UL1998/IEC60730) by integrating the Class B STL library available for U5 series, which is originally intended to satisfy IEC 61518?

Also, this class B contents are available for U5 series in the form of library and not as STL Source files to integrate with our product.

Could you give your suggestion to further proceeding to use U5 series MCU in our product and getting UL1998/IEC60730 certification?

Request you to treat this as an urgent request and expedite.

Thanks in advance.

Best regards,



Hello Support team,

Have a good day.

we have found the UL/IEC60703 certification for the STM32U5 series below the link

But we have some queries which I mentioned below

1. How to run class B library code in a secure region (can I establish a timer ISR and access the class B lib API in ISR Routine? )Please share examples with us if you have any.

2. if we do not enable a trust zone so can I use the same MCU as the non-secure region, also can we able to use dual bank and SBSFU functionality(In Disble trust zone configuration)?

Thanks & Regards


ST Employee

X-CUBE-CLASSB for STM32U5 series is indeed available on

This is the X-CUBE-CLASSB-U5, rev4.0.0, delivered as compiler independant certified object code, with the associated UL certificate.

The package contains project examples with trustzone enabled or trustzone disabled. Please download the package and refer to the readme file and user guide.

Petr Sladecek
ST Employee

Just to add, you can find valid comments at UM2875 as well despite it is dedicated for industrial safety primarily. Concerning dual bank feature, the end customer is responsible for data & code integrity at both the banks, of course. As highlighted at UM2986, at TZEN=1 config, "STL must be executed in secure state. If the STL needs to be executed from a non-secure state, then it must be called via the secure gateway (SG) feature."

Kind regards,