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Altera_Forum's avatar
Altera_Forum
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15 years ago

DAC output as the external clock input?

I'm using the EP2S60 board now. I'd like to use the onboard DAC (DAC904) output as the external clock input. The DAC output is a square wave. However, the DAC output cannot drive the clock to work properly. Anyone has ideas about this issue? Thank you very much in advance!

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    The DAC output is transformer coupled, with about 2Vpp unloaded output. It's not suited to drive a 3.3V CMOS I/O standard on input. It may work by AC-coupling the DAC output and using a 1.65 bias network at the clock input.