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Altera_Forum
Honored Contributor
14 years agoundesired sidebands on Cyclone IV E PLL output
I am using a PLL in a Cyclone IV E. I have a 20 MHz oscillator connected to a clock-input pin. I am trying to get 200 MHz as the output. For the design, I am using only an ALTPLL megafunction bloc...
Altera_Forum
Honored Contributor
14 years agoThe VCCA regulator I am using actually is an LDO. Oscillations on its output were appearing due to a misinterpretation of its datasheet on my part (incorrect bypass and output cap values). The fact that it was an LDO unfortunately made it one of the last things I suspected.