Agilex 5 Power Rail LC Filters

[Nicole04]

Good day,

The Power Distribution Network Design Guidelines: Agilex 5 FPGAs and SoCs document gives the recommended decoupling capacitors and LC filters. In section 2.4, no mention is made of an LC filter requirement for the VCCPLLDIG_HPS supply.

However, in the LC filter recommendation section, the following is recommended:

Should an LC filter be added for these lines?

For which switching frequencies will no resonance occur due to the LC filter?

Kind regards,

Nicole

[FvM]

Hi,
the shown table has apparently errors, corrected in latest release.

220 ferrite bead (22 ohm@100 MHz) can be modelled as lossy 35 nH inductance, resonance in some 100 kHz range.

 

[Nicole04]

Thank you very much. So if my switching frequency is in the 1.5MHz to 2.4MHz range, this bead should work sufficiently?

[FvM]

Hi,
I won't expect relevant current spectal components in the low MHz range. Also, digital power supplies are not so critical, analog PLL would be my major concern.  

[Fakhrul]

Hi Nicole04,

Thanks to FvM for the helpful answer!

I just wanted to check if you have any further questions or concerns regarding this case. Please don’t hesitate to let us know if there’s anything else we can assist you with.

If we don’t hear back from you soon, this thread will be marked inactive and transitioned to community support.

Thank you for your understanding.

Best regards,

Fakhrul