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Altera_Forum's avatar
Altera_Forum
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12 years ago

Cyclone III VCCA current?

I power 4 PLLs of a Cyclone III VCCA with a 50mA LDO regulator. I only use 1 PLL. What current should I supply? 50mA should be fine? I can't find details of the VCCA consumption in the datash...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

Thanks,

the PowerPlay tells me 35mA, so I'm OK

I had already set Preset Low in the megawizard,

monitoring the power supplies VCCA and VCCD_PLL - I could see no glitches - I tried adding 2 x 100n caps (0402 to the bottom of the BGA!) to no affect

I think I have finally solved it with a 22R resistor in series with the 40MHz oscillator. It looks like poor routing of the clock on the PCB.

Thanks again for the advice