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Altera_Forum
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10 years ago

Generating 400MHz external clock (Cyclone V)

Hello, I'm trying to generate a 400MHz clock signal from my Cyclone V in order to drive the clock input for an external ADC, but I'm getting severe attenuation on the clock signal. Details: ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
10 years ago

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I concur with Dave's observation about scope bandwidth. Also, your 15pf looks like about 26 ohms at 400Mhz, a stiff load for an FPGA output.

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Here is a link to an article discussing this kind of measurements: http://www.eetimes.com/document.asp?doc_id=1272404

We always use this technique to probe our circuits.

Regards,

Josy