Analog Devices ADRV9005 Reference Manual page 312

Reference Manual
POWER-SUPPLY RECOMMENDATIONS
Power Domain Filtering
C/FB/C/FB cascaded filters followed by high-current FBs further isolate power signals to the ADRV9001 from each other.
filtered approach implemented on an EVB.
Figure 296. An Example of Power Domain Filtering Implemented on ADRV9001 EVB (1.3V -> VRFVCO2_1P3)
Figure 297 shows a simulation schematic with power-supply filter components used on the EVB power rails in the ADS environment. It attempts
to simulate the frequency response of the filter outlined in
Locate the E1, C1, E2, and C2 elements right at each rail input pin.
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Locate the E3 and C4 elements right at the trace that feeds the particular pin.
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Place the C4 element as the RF capacitor right at each ADRV9001 pin using the rail. For more information about placing these capacitors,
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see the PCB layout section and EVB PCB file itself.
The combined DC resistance of the three ferrites is 0.106 Ω.
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Finally, Figure 298 shows the results of the simulation described in
capacitors. The region >1 GHz outlines the performance of the implemented cascaded C/FB/C/FB filtering approach.
Take care when introducing multiple inductors and FBs in series, as it creates issues with potential I x R voltage drops on them that can
violate the recommended power domain voltage accuracy. The power-supply solution on the ADRV9001 EVB uses the sense line to monitor
the voltage output after the FB (where possible). This approach ensures the voltage drop resulting from the cascaded filters and FB resistance
is taken into account, and the voltage level delivered to the ADRV9001 is in line with the expected accuracy. In scenarios where single-power
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Figure 296.
Figure 297. ADS Model of C/FB/C/FB Cascaded Filter Utilized on ADRV9001 EVBs
Figure 298. Response of C/FB/C/FB Cascaded Filter Utilized on ADRV9001 EVBs
Figure 297. The overall frequency response is better than a typical bank of
ADRV9001
Figure 296 outlines a
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