IMX8MP - PMIC Failure

[Dip_2783]

Hi All,

We are using IMX8M in our design and using PCA9450 PMIC to power it ON. Our device is operated on 12VDC. We are facing issue that if the device is powered up on 12V battery then many time while device is turn on-off, PMIC IC is gets damaged. Here, our observation is that only PMIC is getting damaged no other IC or components has any issue. If we replace PMIC then board start working. We have checked power design there is no issue on that side. Can anyone has faced similar issue. What can be done to solve the issue.

Thanks. 

[Chavira]

Hi @Dip_2783!

Thank you for contacting NXP Support!

Could you please share your schematic showing how the battery is connected to the PMIC?

The VSYS pins on the PMIC support a maximum input voltage of 6V. How are you stepping down the 12V battery to ensure it stays within the safe operating range (6V or less)?

Looking forward to your schematic so we can assist you further.

Best regards,
Chavira

[Dip_2783]

Hi Chavira,

Please find the attached schematic FYR.

Note that we connect 12V battery on VIN+ and VIN-.

Regards

Dip

[Chavira]

Hi @Dip_2783!

I’ve noticed that several power rails (3.3VDC, 1.8VDC, VPP_2V85, and VPP_2V5) remain active at all times.

These power signals should not be connected to any peripherals that interface directly with the processor, especially during power up/down sequences.

Could you please share the connection details or schematics showing where these power rails are routed?

Additionally, can you confirm whether any of these power signals might be interfering with the PMIC during shutdown? This could potentially explain the issues we’re observing.

Looking forward to your feedback.

Best regards!

Chavira

[Dip_2783]

Hi @Chavira,

Regarding Power rails connection. As you know 5VDC is used to power-up the PMIC.

3.3VDC and 1.8VDC is used as a pull-up or peripherals IC power supply.

While the power rail VPP_2V5 is used to power-up DDR4 & VPP_2P85 is used in Ethernet PHY.

What we observed is that Device is running properly on DC and PoE but when it is powered up on 12V battery it runs smoothly many times but sometime while doing turn-on/off suddenly it stops working. This failure is observed only on Battery not on any other supply.

Thanks 

[Chavira]

Hi @Dip_2783!

Please make sure to follow the correct power-up and power-down sequence. No voltage rail should remain active if the processor or PMIC is turning on or off. Additionally, power rails acitve should not be connected to any peripheral that could interfere with the PMIC or processor inputs/outputs.

If you'd like, you can request a schematic review through our case portal. We can help verify your connections and suggest any necessary changes.

Best regards,
Chavira