S32K312 broken

[NamNam]

Hi S32K312 team,

I broke 2 boards S32K312 EVB Q172 within 3 months. All of them have the same phenomenon that the source IC FS26 is very hot, which can burn my finger if touched.
The computer still detects the COM port, but uploading the code from the S32DS fails.

The resistance between VDD_HV_A_MCU and GND is only 6 ohm. We have J18 as a 3.3V or 5V selector jumper for the MCU power. I removed it so there is no supply power to the MCU. Then the IC FS26 is not hot.
I suspect that either the S32K312 IC is dead or the voltage stabilizer capacitors for the 3.3V pins have failed. After gradually removing the capacitors C16, C114, C101, C99, C100, C3857 and U5 ... I determined that IC S32K312 is exactly the cause of the hot source FS26. Both board broke while I was running my code, it worked fine a long time ago with this code. No problem with power via USB port and DC12V port.
Notice that the board failures came when I was using the connection to a hat board (add onboard) plugged in. But I have connected the add-on board many times before. It has an antenna that reads NFC tags. Could a strong electromagnetic field damage the IC?. I'm not sure that's the reason. Just wanted to provide enough information so that we do not miss any clues.

Any questions or suggestions to determine the reason for the board failure is high appreciated.

Currently S32K3123 EVB Q172 is very difficult to find on the market, so it is very difficult for me at work.
Thank you.

[danielmartynek]

Hi Nam,

What was the possition of J18?

You write: "We have J18 as a 3.3V or 5V selector jumper for the MCU power."

The VDD_HV_A must be 3.3V because of the NCx3321.

Regards,

Daniel

[NamNam]

Jumper always select 3.3V sir.
But as i know, S32K312 and NCF3321 can work at 5V.

[danielmartynek]

Hello @NamNam,

Hard to say, the MCU can be shorted accidentally by a loose wire, for example.

What is your usual setup?

Do you drive any external inductive / capacitive loads on the pins with the VDD_HV_A domain?

Regards,

Daniel

[NamNam]

Hello sir, i'm just updated detail about it in post.

Board S32K312 EVB Q172 connect with hat board in top (just have IC NCx3321 and antenna, current comsumption very small). Im do this many time before, and all it run nomaly.

Regards,

NamNam

[danielmartynek]

Hello Nam,

I think you could accidently short some signals, like the VDD power supply to the GND.

Where can I find the schematic of the hat board?

Regards,

Daniel

[NamNam]

Im just update picture in post.
I also thought of the case of double on fet, which is the phenomenon of 2 valves leading at the same time.
Between the hat board and the S32K3 there is an SPI interface and some reset and input pins (pin IRQ in schematic picture). But please note that we have been using them for a long time (6 months) without any problems.