RIPPLES IN SUPPLY OF FPGA_plz help

Hello, I also use a stratix 2 device (speed 3 bg1508).

The voltage drop is quite high on this device, especially if the dc to dc are far away(15 cm)

from the fpga.

On my board, the drop is about 0.2V.

To fix this, you can increase the voltage at the output of your dc to dc.

Personnaly I have 1.4 V after the fuse of the dc to dc, and 1.2 V at the fpga side.

Rippling is caused by a bad configuration of your dc to dc, we had the same issue.

You probably forgot an extra rc at the dc to dc chip.

Before we had a big rippling, and the fpga was far from stable (especially the clock after two pll in cascade).

And before, when I had 1.0V at the fpga side, the entire device was not stable

(because I'm just at the clock max f in the timing report).