NRF52840 Power Section Heating

[K_j]

Hi,

I have a NRF52840-DK (400236). I was using it  for  the development. It was working perfectly.

Suddenly the issue arises the power section is heating up.

I am powering the board up with USB power connected to my laptop.

Specifically the U19 chip is heating up.

SW8 is ON position, SW9 is VDD position.

No battery connected.

Initially the board powers on but after around 5 seconds it powers off.

What could be the possible issue.

[K_j]

Hi,

I have found out that U8 (mux) was the culprit.

after removing the chip board is working fine.
but now i am facing the issue that the UART is not working and CTS pin was using that chip.

Is the replacement chip mandatory. Because i don't have the replacement with me right now.Ordering one will take time.

I need to get this project completed.

if there is a workaround that i can manually jump a trace to get that working.

Kindly Help me out.

[Priyanka]

Hi Kunal,

Sorry for the delayed response. It's the vacation period and many are on vacation now.

Glad to hear that you figured out the heating issue. As for the UART, you can always interface an external UART device to the DK. Could you provide your DK version too?

Best Regards,

Priyanka

[K_j]

Hi Priyanka,

Thanks for the response.

The board version is 2.0.1

I have also got the external UART working.
The board is working fine.

But still need to figure out why the U8 chip failed.

Thanks for the support.

Regards

Kunal