Review the nRF52832-CIAA impedance matching circuit

RE: Review the nRF52832-CIAA impedance matching circuit

SHYAM THILLAINATHAN — Thu, 02 Mar 2017 09:18:24 GMT

Hi Roger,

Thanks for the suggestion, myPage answered most of my questions.

RE: Review the nRF52832-CIAA impedance matching circuit

SHYAM THILLAINATHAN — Thu, 02 Mar 2017 09:17:32 GMT

Hi Kristin,

Thank you so much for the feedback, I implemented the matching circuit according to the reference design, since this is a DEV BOARD that I am building, I am planning to use a SMA connecter O/P. The PCB guidelines page was useful. Much appreciated for your help.

RE: Review the nRF52832-CIAA impedance matching circuit

FormerMember — Thu, 02 Mar 2017 08:19:39 GMT

The general rule for a schematic is that it should be a copy of our reference schematic. It means that on the ANT pin, there should be a LC-filter, C = 1.0 pF and L = 3.3 nH. In addition, a matching network for the antenna is needed, in your case it's a pi-filter and it consists of C33, L13, and C34.

I would recommend you to go through the shcematic and make sure that it is a copy of the reference schematic. The reference layout and schematic can be found here.

It can also be useful to have a look at this tutorial (General PCB design guidelines for nRF52).

RE: Review the nRF52832-CIAA impedance matching circuit

Roger Clark — Mon, 27 Feb 2017 02:14:28 GMT

No worries

I think you best option is to register on Noric's MyPage support system

www.nordicsemi.com/.../register

And send this as a support request, including you gerber file for the PCB (as I don't think they accept anything other than Altium files)

I'm now using KiCad, because the cost of Altium is prohibitive on niche products. (Previously I'd been using Eagle)

BTW. I was a bit surprised about the way you designed your schematic symbol for the nRF52832, as it doesn't look anything like the schematic symbol that Nordic have published

I know the schematic symbol does not need to look anything like the physical footprint, but as component placement is critical on these devices, I suspect that Nordic made the schematic and physical representation virtually the same to help with the translation of the schematic to the PCB design.

RE: Review the nRF52832-CIAA impedance matching circuit

SHYAM THILLAINATHAN — Sun, 26 Feb 2017 23:58:20 GMT

Hi Roger,

Thank you so much for the comment, I am using OrCAD and Allegra. The reason for posting this question is because, I have a space constraint and I am trying to remove L4, L5, C30 and C35. The traces are fairly thin and I would like to know if we can match and tune the circuit with L13, C33 and C34. The antenna I use is a chip antenna from ethertronics.

RE: Review the nRF52832-CIAA impedance matching circuit

Roger Clark — Sun, 26 Feb 2017 23:44:17 GMT

Just curious. What Cad package you are using ?

Also.

I asked a similar question, though for the nRF52840 directly on the MyPage support, but Nordic require Gerbers or Altium files before they would review the schematic. i.e I don't think they can simply review a schematic on its own, and you would also need to include details of the part numbers of the components you intend to use for the antenna circuit etc