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Ref design with chip antenna for cc2541

Sreejith Narayan
Prodigy 30 points

Other Parts Discussed in Thread: CC2541, CC2540

Hi,

Is there a reference design with chip antenna for cc2541?

Can Fractus Compact Reach XtendTM chip antenna (FR05-S1-N-0-102) can be used with cc2541?

If so, can I connect one end of my chip antenna as per the attached figure?

Please help me on this as i am not an expert in RF design

Thanks and Regards,

KNS

  • 0
    Guru 31280 points

    Hi,

    Sreejith Narayan said:
    Is there a reference design with chip antenna for cc2541?

    I think there is no such design.

    Sreejith Narayan said:

    Can Fractus Compact Reach XtendTM chip antenna (FR05-S1-N-0-102) can be used with cc2541?

    If so, can I connect one end of my chip antenna as per the attached figure?

    The fractus antenna can be connected to the feed point, the other end goes to the ground.

    If you (your firm) lacks the experience/equipment/know how to make a good RF PCB design, you should

    start from exploring the "CC2540 USB Dongle reference design", learn it and copy as close as possible with

    the change of the PCB antenna to fractus chip antenna. The layout for CC2540 and CC2541 should be the same,

    except the USB part of CC2540, which is I2C on cc2541.
     

    Pay attention on B1, C5 and R9 components.

    B1 is a balun, which is used for matching the impedance of the CC2540 to 50Ohm impedance of an atenna

    (Fractus chip antennas' impedance are 50Ohms too). The C5 and R9 are part of the fine tuning filter, when

    the manufacturing of PCB is done and all parts assembled you'll be using (hopefully not) this filter to correct

    the impedance matching. The right side of R9 is a feed point for the antenna. Fractus provides you with laoyout

    recommendations for this specific antenna, follow this recommendations.
     

    The balun (B1) in this design is from Johnason, there are other baluns that can be used along with cc254x family,

    such as TDK's and Murata's (go over their prices). I think that each balun requires its own layout (to be more

    specific, vias placement) although all these baluns are of the same footprint.


    Start with something, and then keep on asking questions, RF guys (unfortunately I'm not one of them) will gladly

    have their opinion on your design.

  • 0 in reply to Igor Sherer
    TI__Guru 57865 points

    Sreejith,

    If you do follow the suggestion by Igor

    Igor Sherer said:
    exploring the "CC2540 USB Dongle reference design", learn it and copy as close as possible

     

    please note to add a 32.768 kHz for low power mode (as the CC2540 USB Dongle is missing that). 

  • 0 in reply to Igor Sherer
    Prodigy 30 points

    Hi Igor,

    Thanks a lot for your detailed response. I will follow the CC2540 USB Dongle reference design.

    May have more doubts once I progress further with my design.

    Thanks and Regards,

    Sreejith

  • 0 in reply to J Lindh
    Prodigy 30 points

    Hi Nick,

    Thanks a lot for your support.

    I may have more doubts once I progress with the design

    Thanks and Regards,

    Sreejith

  • 0 in reply to Sreejith Narayan
    Genius 4125 points

    The amount of effort you go to on the RF side should be balanced up against what you are trying to achieve. If maximum range is very important to you then you will need to have it optimized by an RF engineer. If not then simply go off the chip antenna manufacturer guidance and keep to the TI recommended layout as much as possible - you should still be able to pass regulatory testing unless you are unlucky.