• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Subscribers 53 subscribers
  • Views 1170 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

CC1200 PCB design

Michele Santucci
Intellectual 675 points
Other Parts Discussed in Thread: CC1200, CC2590, CC1120

Hallo,

I'm going to design a new board for CC1200 starting from the 433Mhz reference design.

I have a number of questions, .. they are not neccessarily related (besides they talk of the same item).

1) since I'm going to use an external antenna and I need to save space canI 'remove' the embeeded antenna and thus shrink the board (until the edge of the pcb comes near the ground planes)?

2) widen the board on the opposite side of the RF section (antennas and so on) ... would lead to an overall performance degradation?

3) is there any design reference for 433MHz antenna diversity support?

Best Regards,

 Mike

  • 0
    TI__Guru**** 317180 points
    1) If you don't need the PCB antenna you can remove it and shrink the board.
    2) Changing the ground plane will impact slightly on antenna performance, a larger groung plane is normally good.
    3) No
  • 0 in reply to TER
    Intellectual 675 points

    Hi TER...

    thanks again:

    1) ok... this lead to another question (since I would like to design the more 'general purpose' board I can)... the only differences between CC120xEM 420-470MHz and CC100xEM 868-915MHz is on some discrete components in the RF 'section' (L191, L192, L201, L193, C191, C201, C181, C174, C176, L172, L171, R171, C173, C175, L174) while the PCB layout is basically the same (apart embedded antenna and some minor shift of the whole design). There's a method to calculate passive components values to adapt the board to other frequencies (168MHz etc)?


    2) basically I would remove the area in the upper part (those with the pcb antenna) and add the same amount of surface in the opposite site to house a microcontroller. Of course the area will be fully 'ground-planed'.

    3) I found a CC2590 design reference using AN222-92 as the antenna switch (2.4GHz based solution) do you think this can be used as a general startup point to design a 433MHz diversity pcb ? Of course the focal point is 'how to connect the antenna port of the cc1200 to the switching section' (I will NOT use AN222-92 of course). What are your reccomendations?

    P.S. I already designed a CC1200 420-470 MHz board 'variation' using U.FL connector instead SMA ... do you think using U.FL can have negative feedback on the board? 


    Best Regards,
    Michele

  • 0 in reply to Michele Santucci
    TI__Guru**** 317180 points

    1) For 169 MHz use the CC1120 ref design here: to find the component values in the RF network.

    Just remember that the loopfiler cap  and the xtal is different from CC1120 and CC1200.

  • 0 in reply to TER
    Intellectual 675 points

    Hallo TER,

    thanks this's an interesting hint. I would really like to try this carrier frequency and see how far this can lead !

    Besides this I have a more technical question for you.

    I'm going to print a new set of CC1200 board (433MHz ones) with a different PCB print service that's more competent in RF products manufacturing ... they stated that DE104i material is a phased out product and thus suggest me to change it with IS400. The stack  DK is 0,3 mm with Er= 4,35  and prepreg 7628  has Er=4,4 ( @1 GHz ). Do you think that this stack should compromise the overall performance?

    Best Regards,

     Michele Santucci

  • 0 in reply to Michele Santucci
    TI__Mastermind 33150 points
    The difference in the dielectric from Er= 4.35 to 4.40 will have very little effect on the RF performance.

    Keep the PCB thickness the same for both materials.

    Regards,
    Richard