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CC1120: CC1120 : balun @ BALF-112X-02D3 EOL ??? @433Mhz

Part Number: CC1120
Other Parts Discussed in Thread: CC1175, CC1125, CC1200


We are using the BALF-112X-02D3 balun from STMicroelectronics, but it has become obsolete and cannot be found...

Impossible to find an equivalent, if someone has this problem and found a solution, I'm interested.

A 433Mhz balun which saves a lot of coins.


  • Hi,

    The BALF-112X-02D3 was never released for the CC1120 from TI. There is no matched conjugate filter balun at 433 MHz for CC1120; only at 868/915 MHz. 

    The supported matched conjugate filter baluns (IPCs) are listed in Section 8 in the SWRA640 app note.

  • Hi RGW,

    In the data sheet HALF-112X-0203, Matching impedance has been customized for the CC1120, CC1125, CC1175 and CC1200 transceivers from Texas Instruments.

    I saw app note SWRA640, but it's only for 866 Mhz!!!, nothing for 433Mhz, while the CC1120 does mutch frequencies???

  • Agree that the impedance was conjugate matched for HALF-112X-0203 with the CC1120, but this was never approved from TI.

    We always have to work with third parties for these type of filters and there has to be a business case behind each one in order to justify making the IPC.

    There are newer chipsets such as CC1352x that have 433 MHz and 2.4 GHz into one IPC filter (LFB21433MDZ6F112). This might not help as a replacement but could be a future option if there is a design change.

  • I agree with you on the fact that this balun has not been approved by TI, but I find myself in a dead end or the Balun BALF-112X-0203 is no longer available, no possibility to modify the software .

    The simplest solution is to find a CC1120 compatible balun for 433Mhz.

    The project is already in mass production and the simplest is a new design of the PCB with a new balun.

    Do you know a balun for the CC1120 in 433Mhz?

  • Hi,

    If this is a large opportunity then you could always approach Johanson to see if they can make a similar filter but this will take several months.

    How much loss can you accept in the 433 MHz band ? 433 MHz is normally a low-power band compared to 868 MHz. Can you use a 868 MHz IPC and take the extra IL loss at 433 MHz. You would also need to add a 868 MHz notch if you choose this solution. Not the perfect solution but a work-around if you can accept the extra IL at 433 MHz.

    Alternatively, design in the standard passive network for optimum performance at 433 MHz.