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CC1200 RX implement without TX

user3839897
Prodigy 140 points
Other Parts Discussed in Thread: CC1200

Hi, 

I would like to use CC1200 as a receiver without TX.

I find  the Forum "CC1200 separate antennas for RX/TX",and I checked the answer.

According to the SCHEMATIC - CC112x SKY65313 EM 915MHz 30dBm Rev3p0.pdf ,

antenna matching circuit and its value of LC are same as the CC120xEM_868_930_schematic_1_1_0.pdf.

As my application does not need TX,I want to delete TX matching network components.

Is it possible to match CC1200 LNA and 50 ohms antenna by L191-L193/L201/C191/C201

and delete C181 and not to connect TRX_SW in  the reference circuit of CC120xEM_868_930_schematic_1_1_0.pdf.

And as an another matching circuit using 0900PC15J0013 (JTI's balun),

is it possible to delete L171/R171/C171-C172 in Figure 3. in the design note DN039 ?

Thanks for your help.

  • 0
    TI__Mastermind 27145 points

    Hi,

    The junction of C191/L201 should be a 50 ohms port. So this can be tied to 50 ohms Antenna port. I recommend to use PI section ( as a place holder for Antenna matching/Filter) in between C191/L201 junction and the Antenna port.

    PA bias circuit mat not be required for Receive only operation. Bit I will verfify and update you again.

     

    Thanks,

    PM

  • 0 in reply to PM
    TI__Mastermind 27145 points

    Hi,

    Yes, I verified. PA bias circuit is not required for Receive only operation. So, you can delete L171, R171 and other associated circuit.

    Thanks,

    PM

  • 0 in reply to PM
    Prodigy 140 points

    Hi,

    Thank you very much for your reply.

    My understanding is that 50 ohms antenna port should be connected to L193,not to the junction of C191/L201,

    In swrr110.zip (CC112x SKY65313 EM 915 MHz 30dBm Rev3p0.pdf) RX3 is connected to L5 port which is

    the another port of the junction of L4/C1. RX3 impedance is 50 ohms.

    I think that CC1200 is basicaly same as CC112x.

    Is my understanding is right or not?

    Thanks,

  • 0 in reply to PM
    Prodigy 140 points
    Thank you very much for your reply.