We are considering the ADF4355-3 for use as a LO source and would appreciate clarification of the VRF supply requirements. The datasheet states VRF must be the same value as AVDD, which in turn must be the same as DVDD. However the datasheet also recommends that different regulators are used for VRF and DVDD.
If we were to use one regulator for AVDD and DVDD and a different supply for VRF is this ok/recommended and/or are there any requirements regarding supply sequencing and/or maximum deviation between AVDD and VRF (in the architecture being considered it is likely that AVDD/DVDD will be fully powered up before VRF)?
We also intend to use a dedicated regulator for the VP and VVCO supplies as recommended (which also means we can support the 5V ADF4355 if necessary). I presume that this supply can be powered up/down independently to the other supplies?
Thanks in advance