NRF5340 IC in WLCSP 4.4 x 4.0 mm package, Board Fabrication

[KostasH]

Has a community member implemented and fabricated the nRF5340 IC in the WLCSP package that has its pad landings spaced at a 350um ?

If so, can you share design guidelines for embedded micro-vias in the IC's pads to fan out the various signal and supply traces ?

Are there any recommendations for a particular PCB vendor that can fabricate an FR-4 or LPC PCB using the nRF5340 in WLCSP ?

Thank you ! 

[Bendik Heiskel]

Hi,

We Altium design files and gerber production files available for our reference layout. They can be downloaded from the product page:

https://www.nordicsemi.com/Products/nRF5340/Downloads#infotabs

The blind vias used to fan out the inner GPIO lines are 0.25mm in diameter and have a drill size of 0.1mm.

The 4 GND vias used for the center ground pins are 0.5mm in diameter and 0.25mm drill size.

Are there any recommendations for a particular PCB vendor that can fabricate an FR-4 or LPC PCB using the nRF5340 in WLCSP ?

I do unfortunately not have any specific PCB vendors to recommend to you.

 

Best regards,

Bendik

[KostasH]

Hi Bendik,

Thank you for sharing the reference design with the WLCSP version of the IC. There seem to be embedded vias in some pad landings and their OD=250um exceeds that of the other IC pads which are at OD=170um, this shouldn't be an issue the openings are solder-mask-defined depending on the board fabricator's recommendations.

Best regards,

Kostas