Honored Contributor
Honored ContributorThe ripple you are seeing could come from a number of contributors. Most often dc-dc supply is undersized (LC too small or freq too low). What frequeny is the ripple you see? Less than 1MHz your dc-dc convertor is the prime suspect.
You should also make sure you don't have any shorted i/o. I always tell Quartus to set all unused io to tristated inputs rather than the default outputs driving ground. If the ripple/noise you see is much higher like 10's of MHz+ then you should examine your power supply filtering and decoupling. Hope this helps, Chris
