Clarification on nRF52820 Reference Schematics and Layout

[prabhakar kumar]

Query on reference designs and layouts

1. "nRF52833-QDAA Reference Layout 1_0 PCB" stack-up seems to need improvement (please check the Core thickness between Layer1 and Layer2. Whereas "nRF52833-QIAA Reference Layout 1_0" looks reasonable. Since we are using nRF52820-QDAA package, pls advise a reasonable reference layout. (reference Nordic website and NRF528xx reference design)
2. Seems L3 and L4 need to be swapped (L4 to be connected to U1-Pin 39 and L3 to the filter capacitors. (Reference nRF52820 datasheet, " Figure 149: Circuit configuration no. 2 schematics for QDAA QFN40 ")

Please correct me if my understanding is wrong and convince me with a suitable explanation.

General query
1. Is there any Nordic (or any third party) DVK with nRF52820 MCU?

Thanks

[Kaja]

Hi,

1. Could you elaborate what you mean here? 
Here is the layer stack:

2. The correct is to attach L3 closes to pin 39. L3 is needed for the internal regulator to function properly, and L4 is used as an RF choke, to reject noise from entering the radio. These need to be 10 µH and 15 nH respectively. This has been verified through simulations during chip design and internal testing.

There is no separate development kit for the nRF52820 chip. Projects for nRF52820 can be developed on the nRF52833 DK.

Best regards,
Kaja

[prabhakar kumar]

Hello Kaja,

Thanks for the reply.

Could you please let me know the DC-DC switching frequency?

Thanks

[Kaja]

Hi,

prabhakar kumar said:

Could you please let me know the DC-DC switching frequency?

 -  8 MHz

Best regards,
Kaja

[prabhakar kumar]

Thanks a lot!