Hello,
I am attempting to develop an open source nRF52832 PCB design, aiming to minimize the footprint as much as possible.
Thus, I attempted to cramp as many components in a tight space as possible.
I know that my design, deviating from the reference PCB, probably sacrifices quite a bit of RF quality and signal strength.
Yet, I wanted to ask Nordics opinion on this design, and what I could improve.
Thanks a lot!nrf52_micro.zip
We will happily have a look at this and do our best to help you reach you goal here
probably sacrifices quite a bit of RF quality and signal strength.
You made a very compact design here so RF performance will likely suffer. I see that you are using a chip antenna, can you link to the antenna of choice?
Most Nordic products have their own radio matching network, and the antennas often have their own as well so usually you would need to add the recommended components for the antenna of choice.
See https://devzone.nordicsemi.com/guides/hardware-design-test-and-measuring/b/nrf5x/posts/general-pcb-design-guidelines-for-nrf52-series for some more details on what we recommend.
https://devzone.nordicsemi.com/guides/hardware-design-test-and-measuring/b/nrf5x/posts/nrf52832-specific-pcb-guidelines
Also maybe have a look at our nRF52805 CSP variant, its small. https://devzone.nordicsemi.com/guides/hardware-design-test-and-measuring/b/nrf5x/posts/nrf52805-specific-pcb-guidelines , here it also shows the LDO setup https://docs.nordicsemi.com/bundle/ps_nrf52805/page/ref_circuitry.html#ariaid-title5
If you want the area even smaller you can mount some of the components like the crystal on the bottom layer.
What is the goal here in terms of RF performance?
Also, you do not have access to the programming pins here, SWDIO and SWDCLK, unless the SoC comes pre-programmed this will be difficult to work with.
Regards,
Jonathan
Thanks a lot, I really appreciate the feedback!
1. I have linked the datasheets of all components in the kicad schematic, if I am not mistaken. Could you please check there? If I recall correctly, I was intending to use 2450AT18A100, which should be pre-tuned to 50 ohms.
2. I could mount components on the bottom, but would that not make the whole module unmountable?
3. This board is just a prototype, and I have no specific RF goals in mind. I just need a few meters of connection. Could you give me some sort of scale on what to expect here, given the provided chip antenna?
4. Oh, I must have missed the debug pins. My bad...
Again, thanks a lot! For a first attempt of designing something like this, it is really overwhelming. Help like this really helps to understand a lot of things!
I don't see anything unique here, seems like the goal was to get it as square and compact as possible.
But 10 + meters is not exactly great when it comes to range, its possible to achieve far more with so the performance does reflect the design here.
I went looking and I do see we have a few tickets here on Devzone with the HolyIoT module, and this one comments on the range https://devzone.nordicsemi.com/f/nordic-q-a/64465/nrf52832-outdoor-range. I would suspect that a similarly sized design would perform the same with a similar antenna.
If you want we do help with tuning, so you can send a unit or two to us and we can try and optimize the matching components for the radio here, might be able to squeeze out some extra power so that you get the best range. This is best done by just adjusting the radio matching components.
Also operating at a higher voltage does yield some more power.
Regards,
Jonathan
Hello,
sorry, this took a while to get back to.
I would love to take you up on the offer of optimization.
What would be the next steps here?
Could I order straight from JLCPCB to you?
Thanks!
Hi,
Daniel Dakhno said:Could I order straight from JLCPCB to you?
This can be done, you can decide what you think is the best option for you here.
We usually need a 2 devices, but since this is so small it is good to have a backup or two, so 3-4 devices just to make sure that we dont have to ask for extra devices.
What we can do is have a look at the performance and provide a report, we do conducted testing for the radio and antenna and we will provide recommendations to components as to what would be a improvement if there is any significant performance boost to get.
Regards,
Jonathan
Hello,
Thanks for the information.
Do you require fully assembled devices?
If that is the case, you probably also need a firmware pre-flashed?
Cheers!
Daniel Dakhno said:Do you require fully assembled devices?
It is best if it is populated with all the components related to the nRF SoC and antenna. So in this case it would be best. But we can replace some parts if needed or populate some parts if needed, its just not something we have capacity to do for everyone all the time.
Daniel Dakhno said:If that is the case, you probably also need a firmware pre-flashed?
If we can asses the SWD lines we dont need anything to be pre-flashed on to the device, so for this i guess we would need something pre flashed.
Regards,
Jonathan
Daniel Dakhno said:Do you require fully assembled devices?
It is best if it is populated with all the components related to the nRF SoC and antenna. So in this case it would be best. But we can replace some parts if needed or populate some parts if needed, its just not something we have capacity to do for everyone all the time.
Daniel Dakhno said:If that is the case, you probably also need a firmware pre-flashed?
If we can asses the SWD lines we dont need anything to be pre-flashed on to the device, so for this i guess we would need something pre flashed.
Regards,
Jonathan
