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TRF371109 Ambiguities

Other Parts Discussed in Thread: TRF371109, TRF3710

I am desiging a prototype receiver based on the TRF371109 direct conversion receiver/ IQ demodulator.  

 

The datasheet lists pins 42 and 43 as NC's but the evaluation board has them both labeled as BBIinn and BBIinp, BBIinp has circuitry connected to it.  Are these pins NC's or is there functionality associated with them that I need to be concerned with?  The datasheet provides zero information.

 

What is the purpose of the MIXIOUTP/N and MIXQOUTP/N outputs?  Are they only for testing?

 

There is no description of the CHIP_EN pin, is it active high or low?

 

Thanks

 

Rich

  • Richard:

    Pins 42 and 43 are truly no connects for the TRF3711 family; there is no internal connections in the device.  The EVM board is used to service the TRF3711 and the TRF3710 device.  The TRF3710 device uses one of those pins for Readback and that is why there is circuitry connected to it.  The names are legacy from previous TRF3710 versions that did actually use those as a BB input.

    The MixOut pins can be used to see the output of the demod before the signal goes through the BB section.  Initially these ports were designed to be used as a way to bypass the BB filter to get more signal bandwidth.  The bandwidth is limited by the output buffer at around 50 MHz.  These outputs are rarely used as the TRF3711 incorporates a filter bypass feature that allows a signal bandwidth around 30 MHz

    When chip_en is tied high then the device is active.  When tied low or open circuit the device will be disabled.

    Regards,

    Russell

  • Russell,

       Sorry for the delay.  That is all very helpful, thank you.

     

    Rich