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TRF7970A: Schamtics as reciever

Takeo Sekiguchi
Expert 3305 points
Part Number: TRF7970A

Hello,

1) Is there any reference schematics, impedance matching and smith chart information as reciever?

    If not, could you provide the proper values of C15, C16, C17, C19, C20, C21 as reciever in Fig 7-1. Application schematic and smith chart?

2) What is RX_IN1/RX_IN2 status during transmitting (Z, open, or...)?

3) What is TX_OUT pin status during recieving (Z, open, or..)?

Regards,

Takeo

  • 0
    TI__Guru*** 135355 points
    Hello Takeo-san,

    1) I am presuming you mean as only a receiver where the TX_OUT pin is not used? If so, no we do not have such a schematic. The matching network is designed to create a 50 ohm impedance point to connect an antenna to and this is done by starting with the 4 ohm impedance from the TX_OUT pin.

    2) I don't think we have ever classified that but I would presume they are open as there is no benefit for them to be high-z.

    3) The TX_OUT will always be open as it needs to be provide the 4 ohm impedance source for the matching network to be accurate.

    It sounds to be like the customer is considering modifying the matching network. If they wish to do this, that is up to them, but from a support standpoint TI will not support any matching networks that deviate from what is provided in the datasheet schematics. Please make that clear to them to set expectations on the level of support we will provide.