NRF52840-QIAA-R Hardware layout

[fshaikh]

Hi, I am developing a PCB based on the NRF52840-QIAA-R package.

The pads are very tightly packed, and I had to shrink the size of the middle ground pad to accomodate vias for NRST and AC15. 

Is this allowable in the design? 

[Asbjørn]

Hello Faheem,

I see you've offset the via from the pad. You should and our recommendation is to use blind vias in these pads and route them through inner layer to where you need to have them. 

I'd recommend that as shrinking the space for the GND pad on the PCB doesn't change the die pad on the chip itself and could in worst case produce shorts between the die pad under that chip and the via you have put in.

Best regards

Asbjørn

[fshaikh]

Thanks for replying. What other options do I have if my board manufacturer doesn't use blind or buried vias? 

[Asbjørn]

Hello Faheem,

Your options could be 

• To look at a different manufacturer?
• Could go ahead and accept the risk that you might have a non functioning board in a small prototype build?
  • If it works and performance is acceptable, then ok. If it doesn't, you can find alternative PCB manufacturers that support making the board dimensions needed.
• You can use QFN version of the chip?

Best regards

Asbjørn