Choosing the Printed Circuit Board (PCB) stack-up should be aligned with the end
product's PCB requirements.
For nRF9160, the following targets should be considered:
- Dedicate one metal layer that is as intact as possible for the common ground layer.
- Consider the need for 50 Ω RF routings. Sometimes to achieve 50 Ω routing requires the
adjacent metal layer to be opened which increases the risk of exposing RF routing to noisy
routings.
- Avoid crossing 50 Ω RF routings on the application board. If it cannot be avoided, ensure
that their ground planes remain continuous.
- Avoid using through vias in RF routings if they cause a parallel stub to the routing or are
not 50 Ω.
- Consider good thermal design and aim to use metal filled vias due to their better thermal
conductivity especially close to nRF9160.