PDN design

Hello there,

I'm working on a Arria V design but I'm a little confused about power supply and PDN requirements.

If I look in the Arria V datasheet, recommended operation conditions for VCC are set to 1.07-1.1-1.13V (min-typ-max). This equates to 3% allowable variation in the VCC voltage. At first glance I would think that I must design so that the voltage is always within this range which means that AC ripple + distribution drop + PSU tolerance must be less than 3%.

However; in the PDN tool, recommended ripple is set to 5% for VCC with an Arria V device. Furthermore this includes only the AC ripple as the value is used directly to calculate the de-cap network.

So; the question is: should the values given under recommended operating conditions only be seen as "DC" requirements setting the level for PSU tolerance and distribution drop. Or should I view recommended operating conditions as "AC" requirements and design so that these values are meet for all frequencies up to F- effective?

If the first is true, shouldn't the datasheet provide a recommendation for AC ripple? If not, why does the PDN tool recommend much higher values?

Hope somebody can clarify :-)