nRF52840 2-layer PCB

[CHEVYAN]

Hello

Just to confirm:

• is it OK to use 2-layer PCB with nRF52840?
• In case a 4-layer is needed, when do you advise the use of a 4-layer pcb?

Basically we'll have the chip + accelerometer/gyro + lipo charger + SPI FLash on a chip of max 3cm x 2cm.

Thanks for your answer.

[Jørn]

Hello Chevyan

Using a 2 layer PCB is OK. A 4 layer PCB will give more freedom when it comes to routing your traces and can make it easier to maintain unbroken ground-planes where needed. Prices are typically higher for multi-layer PCB's.

It is important the RF section has solid ground and is dimensioned properly. Typically you would design RF traces as transmission lines or co-planar waveguides with solid ground underneath. With a multi-layer pcb you could also design them as striplines (completely embedded in the dielectric). The antenna should have a large solid ground plane covering it at least one side. I suggest you read this blogpost for PCB guidelines for the nRF52.

Best regards

Jørn Frøysa