On the ADRV9009 FMC board, there's a VCXO connected to the ADP9528 PLL.
The VCXO's supply pin connects to the VDDA_3P3, which comes from the DC-DC converter ADP5054. That supply is filtered VDDA_3P3 using a ferrite bead (30 ohm) before it reaches the VCXO's supply input.
I'm wondering if using an ADP150 ultra low noise LDO, as suggested in the ADP9528 datasheet, see screenshot below, or is the ferrite bead sufficient and would the ADP150 be overkill for the ADRV9009 applications?
Adding additional LDO depends on your system requirement.
Power supply design for ADRV9009 EVB was aggressive and it gives decent performance for demo purpose and not tested for all extreme conditions.
You can consider having both the option in your design, after validation you can choose one of the approaches.
thank you PVALAVAN for your reply - could you clarify 'aggressive' -> do you mean that cost of the supplye was kept as low as possible, or size? In case we don't need to bother about price and pcb board size, but we need the best solution, are there any other improvements possible?
You can consider deriving supply for AD9528 and VCXO from ADM7154 LDO.
Input to ADM7154 can be from ADP5054.
You can derive below power rails from Ultra Low Noise LDO after ADP5054
Provide each one LDO for 1.8 V, 1.3 V, 3V3 CLOCK, VDD3V3, VDD_INTERFACE.
For better isolation add ferrite beads and provide options for high-value bulk decoupling capacitors for each of the above power rails.