How to identify information printed on STM32F407IGT6 chips?

[Muk]

I have two STM32F407IGT6 chips, and I need help understanding the markings printed on their surfaces.

• Images attached:
  • First chip: "STM32F407IGT6 AA295 VQ 6 TWN AA 342"
  • Second chip: "STM32F407IGT6 VQ249473 AA297 TWN AA 318"

I would like to know:

1. What each line of the markings represents?
2. How to verify the authenticity of these chips?
3. If there are any important differences between these two chips based on the markings?

Any detailed guidance or resources to decode this information would be greatly appreciated. Thank you!

[SofLit]

Hello,

The information needed by the user is provided in the datasheet:

We don't provide detailed explanation. And the two chips are genuine.

Many new chips have 2D QR code marking. for more details you can contact your local FAE/Sales.

[Muk]

Hello,

Thank you for the response. I have already reviewed the datasheet and understand how to read the date/time information printed on the chips.

However, I have a specific question regarding the markings:

• AA295 VQ 6 on one chip.
• VQ249473 AA297 on the other chip.

What do these specific codes represent?

The reason I am asking is that I am using both chips in the same circuit and with identical code, but I am observing a difference in the Ethernet functionality:

• The chip marked AA297 VQ b works with both newer and older switches.
• The chip marked VQ249473 AA297 only works with newer switches.

Could you please explain why there is this difference? Are the markings related to internal revisions or production variations that affect Ethernet compatibility?

Thank you for your assistance!

[Tesla DeLorean · Accepted solution]

VQ if a diffusion plant in France for the wafer

AA29x is a production/packaging plant in Taiwan

You can determine the chip stepping via the DBGMCU / DEV_ID, and associate that with an Errata

https://www.st.com/resource/en/reference_manual/rm0090-stm32f405415-stm32f407417-stm32f427437-and-stm32f429439-advanced-armbased-32bit-mcus-stmicroelectronics.pdf#page=1716

The production date might shed some light on the options enabled on the F4 dies, ie Ethernet,Crypt, etc

[Muk]

Thank you for the clarification. I understand now, and I appreciate your help!