nRF9160 custom hardware and pcb review

[Nikunj]

Hello Nordic Community,

I found  bsd Irrecoverable error on my other ticket

https://devzone.nordicsemi.com/f/nordic-q-a/53913/support-on-nrf9160-irrecoverable-3

I just want to review my custom hardware attached below,

NB-IOT_nrf9160.pdf

Thanks and regards,

Nikunj 

[Andreas]

Hi,

 

Not sure if this is the reason for your troubles, but you need to ground the SiP properly. Multiple vias in the center that go down into the bottom layer ground plane. Also, there can not be any signal traces that pass underneath your RF path. In order for the antenna to work properly you also need to maximize the size of the ground plane, with a board this small though you might be better off using an external antenna.

 

Best regards,

Andreas

[Nikunj]

Hi Andreas,

In my custom board I2C, SPI, GPIO all peripherals are working well so I think there is no ground plane issue.

Andreas said:

Multiple vias in the center that go down into the bottom layer ground plane. Also, there can not be any signal traces that pass underneath your RF path

There is no signal path underneath RF path in my pcb.

bsd error : 3 error is still coming so problem is from hardware side or from firmware side?

How do I suppose to solve that issue?

Thanks,

Nikunj

[Andreas]

Hi,

 

Looking at the bottom sheet of the pdf file you shared, there are 3 signal traces passing underneath the RF path (ANT-pin to antenna):

In any case, grounding is not good and could very well cause your device to crash. This error is not related to one specific module or root cause. You can debug and try to figure out what the cause is, but you either way need to redo your design if you want it to pass certifications. I suggest you take a look at these two documents:

https://www.nordicsemi.com/-/media/Software-and-other-downloads/SiP/nRF9160-SiP/nRF9160-Hardware-integration-guide.pdf

https://infocenter.nordicsemi.com/topic/nwp_033/WP/nwp_033/nwp_033_intro.html?cp=13_0

 

I also suggest that you test your application on a nRF9160-DK and update to the latest modem FW (v1.0.1 as of writing).

 

Best regards,

Andreas