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STM32U0 UFQFPN32 not compatible to L0 variants?!

OliM
Senior

The first idea when watching the STM32 summit an hour ago was of course to directly replace the L0 chips in the projects which are still under development. But it looks like the QFN32 variant is not pin compatible (at all). Pin 1 to 4 and Pin 30 to 32 changes definitely mean a new layout.
Instead the new QFN part recreates the old LQFP Pinout. Is this a datasheet error or a an oversight in the real parts?

OliM_0-1710845775519.png

 

 

1 ACCEPTED SOLUTION

Accepted Solutions
Viktor POHORELY
ST Employee

Thank you for your question and let me explain a bit the situation.

STM32L072xx/STM32L082xx were designed with incompatible pinout due to technical constraints in bonding of the die in this type of package. Therefore, since it has been introduced, it is marked as incompatible with other STM32L0 devices in the datasheet - see note 1 below. It is incompatible even with STM32L4 and other STM32 products in this package.

For this reason, we keep compatibility with majority of STM32L0 and STM32L4 products.

When migrating from L072/L082, or any LQFP with die pad, PCB update or redesign is mandatory.

Sorry about the difficulties but it is neither error in the datasheet, neither an oversight, just simple technical reason as it is difficult to be compatible with both existing pinouts, when one of them was already incompatible with the rest of the portfolio.

Untitled.png

You may also refer to AN6091 - Migrating from STM32L0 to STM32U0 MCUs.

 

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3 REPLIES 3
Viktor POHORELY
ST Employee

Thank you for your question and let me explain a bit the situation.

STM32L072xx/STM32L082xx were designed with incompatible pinout due to technical constraints in bonding of the die in this type of package. Therefore, since it has been introduced, it is marked as incompatible with other STM32L0 devices in the datasheet - see note 1 below. It is incompatible even with STM32L4 and other STM32 products in this package.

For this reason, we keep compatibility with majority of STM32L0 and STM32L4 products.

When migrating from L072/L082, or any LQFP with die pad, PCB update or redesign is mandatory.

Sorry about the difficulties but it is neither error in the datasheet, neither an oversight, just simple technical reason as it is difficult to be compatible with both existing pinouts, when one of them was already incompatible with the rest of the portfolio.

Untitled.png

You may also refer to AN6091 - Migrating from STM32L0 to STM32U0 MCUs.

 

Thank you. I am still no happy that the most obvious upgrade path is the one not available, but I understand the reasoning.

Thank you and sorry about that, although it was based on strong technical reasons, it was not an easy decision indeed.