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trf372017 Frequency range

Giuseppe Cannarella
Prodigy 85 points
Other Parts Discussed in Thread: TRF372017, TRF3765, TRF370417

On trf372017 datasheet there are not reference about external LO frequency specification.

With on board VCO it's possible to cover frequencies from 300 to 4800MHz, but i'ts possible to go down to 50MHz (or better 30MHz) using an external VCO input and use a 10MHz as reference?

There are some limitations on PLL (dividers. etc) and/or mixer, RF blocks?

Thank you.

Giuseppe

 

  • 0
    TI__Expert 3300 points

    The internal VCOs hit a hard limit at 2400MHz minimum and 4800MHz maximum and should not be used beyond those boundaries.

    Using an external VCO, it is possible to extend the minimum frequency down to minimum 30MHz at room temp but only down to 55MHz at high temp. The maximum frequency lies near 6000MHz, across temperature.

    These limitations are results of the Tx Divider between the synthesizer and the quadrature modulator. The synthesizer continues to function beyond these limits with gain rolloff, as in the TRF3765. The TRF3765 synthesizer output rolls off by 20dB at 15MHz and 9000MHz.

    A 10MHz reference input does not create a limitation.

  • 0 in reply to Pete Hanish
    Prodigy 85 points

    Hi Pete,

    thank you for the explanation!!

    Regards.

    Giuseppe

  • 0 in reply to Giuseppe Cannarella
    Prodigy 85 points

    Hi Pete,

    Using an external LO instead of VCO (in this case I will not use the internal PLL but only the I&Q modulator...) there are the same limitations?

  • 0 in reply to Giuseppe Cannarella
    TI__Expert 3300 points

    The modulator will work down to 50MHz with modulator characteristics similar to the TRF370417 and synthesizer / external VCO performance as discussed earlier in this post.