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Category: Datasheet/Specs
Product Number: ADF4355 and ADF4355-3

Please explain what is the difference between ADF4355 and ADF4355-3?

  • Comparing the "Features" block on the first page

    of the two data sheets reveals the following lines

    that are different:


    RF output frequency range: 54 MHz to 6800 MHz

    Analog and digital power supplies: 3.3 V

    Charge pump and VCO power supplies: 5.0 V typical


    RF output frequency range: 51.5625 MHz to 6600 MHz

    All power supplies: 3.3 V

    The "General Description" block on the right-hand side

    of the data sheet reveals the following sentences that are

    different (and also add new information):


    The ADF4355 has an integrated VCO with a fundamental output frequency ranging from 3400 MHz to 6800 MHz.

    The ADF4355 operates with analog and digital power supplies ranging from 3.15 V to 3.45 V, with charge pump and VCO supplies from 4.75 V to 5.25 V


    The ADF4355-3 has an integrated VCO with a fundamental output frequency ranging from 3300 MHz to 6600 MHz

    The ADF4355-3 operates with analog, digital, charge pump, and VCO power supplies ranging from 3.1515 V to 3.4485 V

  • Thanks. But the differences seem to me to be insufficient to warrant a separate chip design!

  • It's unlikely the ADF4355-3 required a new photomask set.

    Modern mixed-signal chips have ways to permanently

    modify the behavior of the chip post-fabrication [1].

    What likely happened here was that a customer wanted to

    use the ADF4355 in a design that did not have a 5V rail available,

    and asked ADI if it was possible to trim a version of the chip that

    worked with all rails at 3.3V with reduced specifications.  Once

    the work was done, there was no reason not to offer the chip

    variant to the entire customer base.