Questions about nRF52833 "Not Connect" pads

[stefel]

The nRF52833 datasheet lists a number of pads as "N.C." however I could not find anything in the datasheet about what to do with these pads. Is it safe to route traces over those pads, or do they have to be lest unconnected? The majority of pads on the nRF52833-QIAA can be routed without the need for micro-vias in pads, and I would like to route some of the inner pins through "N.C". pins to avoid increasing PCB fab cost when using micro-vias. For example, could one run a trace to B17 (P0.23) through A18 (N.C.)?

[Priyanka]

Hi Stephen,

Routing over the N.C pads might not be an issue as they are "Not connected" , but later if in a newer version of the MCU these pins are used, then you will have a hard time re-designing them, i.e. you will have to change the footprint. But also, we do not recommend varying from the reference design too much, since this can cause problems. The N.C pins might or might not have various purposes, like heat dissipation, mechanical stability etc. and varying too much from the reference design can interfere with your performance. 

Regards,

Priyanka