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Altera_Forum
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11 years ago

Vref

Hi I haven't fully understood the concept of the VREF pins. I know this is the threshold voltage at which a voltage referenced IO standard decides between a low or high. But isn't this just...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
11 years ago

As I understand it, the vref voltage should be something defined as per the IO standard used. It seems like for some IO standard ie SSTL-2, it is half the VCCIO instead of 1.25V. You could refer to the device datasheet for further details on the Vref voltage for different voltage referenced IO standard. Look for "Reference Voltage Specifications" keyword in the datasheet.