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LMX2581E: LMX2581E

Ch Ramakrishna
Prodigy 240 points
Part Number: LMX2581E
Other Parts Discussed in Thread: LMX2572

We are planning to use LMX2581E as local oscillator for our super heterodyne architecture..

We need to generate 140MHZ to 240MHZ output frequency with 25MHZ as reference clock..

The frequency resolution of this local oscillator is required at 1Hz step..

Please suggest suitable Loop filter components and the various N & R values required to have better phase noise..

  • 0
    TI__Genius 12550 points

    Hi,

    For the loop filter components you can use the PLLatinum Sim tool. Also for other parameters calculation use the TICS Pro tool, which can provide the register settings for all required frequencies.

    For new designs, consider the LMX2572. It is not pinout or program compatible, but it is lower current, lower spurs, and better PLL noise. Also it has some added features. LMX2572 has PLL_DEN (PLL Fractional Denominator) with 32bits, whereas LMX2581E has 22bits only.

    Thanks!

    Regards,
    Ajeet Pal