How would you recommend powering the many power rails on an ADF4356?

How would you recommend powering the many power rails on an ADF4356? For example, would you advise a single plane for a single voltage rail and do discontinuities make a difference?

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    •  Analog Employees 
    on Mar 27, 2018 10:39 PM over 3 years ago

    On behalf of Ian Collins:

    For the 5V rail, make sure to use a really clean LDO like the ADM7150, HMC1060, or LTC3045.

     

    The 3.3V rail is more forgiving, as it doesn’t power the VCO.

     

    The 1060 is on the 4356 evaluation board, and I recommend that. It contains both the 3.3V and 5V rail which makes it ideal for that part.

  • I also have a question about powering ADF4356.

    With 5V rail all is clear.

    What about 3.3V rail.

    Datasheet says "For the 3.3 V supply pins, use two ADM7170 regulators, one for the DVDD and AVDD supplies and one for VRF. Figure 43 shows the recommended connections."

    But as we can see one of the ADM7170 (VOUT) connected to DVDD and the other (VRF) to AVDD and VRF.

    In evaluation board (EV ADF4356SD1Z) we have one power supply which generates all rails but still unlike datasheet pins AVDD and DVDD connected to one 3.3V rail (VDD) and VRF pins to the other 3.3V rail (VRF).

    So, my question is does it make any difference which of the pins (AVDD, DVDD, VRF) we connect to the same 3.3V rail?

    Which way is the right one, datasheet or evaluation board?

    Regards,

    yuri

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  • I also have a question about powering ADF4356.

    With 5V rail all is clear.

    What about 3.3V rail.

    Datasheet says "For the 3.3 V supply pins, use two ADM7170 regulators, one for the DVDD and AVDD supplies and one for VRF. Figure 43 shows the recommended connections."

    But as we can see one of the ADM7170 (VOUT) connected to DVDD and the other (VRF) to AVDD and VRF.

    In evaluation board (EV ADF4356SD1Z) we have one power supply which generates all rails but still unlike datasheet pins AVDD and DVDD connected to one 3.3V rail (VDD) and VRF pins to the other 3.3V rail (VRF).

    So, my question is does it make any difference which of the pins (AVDD, DVDD, VRF) we connect to the same 3.3V rail?

    Which way is the right one, datasheet or evaluation board?

    Regards,

    yuri

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