MCXN947 LDO_Core Overvoltage

[Vasilis_Skr]

Hello NXP Community,

We are developing an IOT Module that is using the MCXN947VKLT (100 pin HQFP) μCU.

We made a production run of 100 PCBs and 5 out of them show a strange behavior: Their core voltage (VDD_CORE) ranges between 2V and 2.1V instead of having a maximum of 1.2V that is specified in the datasheet.

I removed the inductor LX and checked the core voltage and it is still 2V, which points me to the direction of the internal CORE_LDO circuit.

Is my assumption correct? 

How should we proceed?

Thank you in advance and I am looking forward to hearing back from you!

[carlos_o]

Hi @Vasilis_Skr 

Thank you for your post.

Thank you for sharing the information. Based on the details provided so far, I am unable to reach a conclusive assessment. Additional data or clarification is required to properly analyze the issue.

Please review the solder of the defective PCBs to ensure there is not a connection failure. 

Could you please share your schematic to review the LDO connection? 

If you want a private channel, please open a support ticket.

You could review how to use the ticket system in the following video Tutorial for NXP Support Case Portal | NXP Semiconductors

[Vasilis_Skr]

Hey Carlos,

Thank you for your quick reply.

Here you can find our connections to the μCU regarding power.

I do not expect something to be wrong as this is a rare occurrence we got in 3 out of 125 PCB's that we have produced, but it is still worrying me.

Regarding the soldering of the pins, I have checked the PCB's under a microscope and everything seems fine. I have also asked our PCBA partner to check the GND pad of the μCU with X-Rays to verify the soldering of that pin as well.

Let me know if you have any other insights.

Thanks in advance!