nRF52833 Eagle PCB layout needed - specifically for the RF circuit

[DigiMan]

Hi,

We're designing a PCB for the nRF52833. We could not find a PCB layout recommendation for the chip.

We did find one for the highly similar nRF52840: github.com/.../nrf5-eagle-reference-design

HOWEVER, upon review of the circuit, I noticed that there are two differences, 1 in the rf circuit - the 52840 uses 1inductor and 2 caps, where the 52833 appears to use 2 caps and 2 inductors of different values., and P0.19 appears differently.

devzone.nordicsemi.com/.../eagle-design-block-for-nrf52833

Are there any recommendations for either where I could find a sample PCB layout, or Eagle BRD and SCH file set, for the nrf52833?  OR  how would I go about properly tuning the antenna circuit?  ALSO, if we wanted to put a small jack for an external antenna on the board, would this improve performance, and how would this affect the rf networking matching circuit?

Thanks in advance for any info!

Ted

[ketiljo]

There's no Eagle design for the nRF52833, sorry, so you have to modify the nRF52840 design yourself. Copy the reference layout from https://www.nordicsemi.com/-/media/Software-and-other-downloads/Reference-Layouts/nRF52833/nRF52833-xxAA-Reference-Layout-1_1.zip

[DigiMan]

The link you attached to the reference designs w the PCB layouts is PERFECT! Thank you. This is exactly what I was looking for.

If I wanted to add an external antenna, and a u.FL or w.FL jack on the board, are there any recommendations in how I would go about tuning the antenna, or design the circuit without pulling my textbooks on antenna design and tuning?

Thanks in advance,

Ted

[ketiljo]

If you're using an external antenna with a U.FL connector, just place the connector right after the matching network. Any matching of the antenna must take place on the antenna itself, i.e. after the coax cable. The placement of the antenna is somewhat important so consult the antenna datasheet for this.