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Altera_Forum's avatar
Altera_Forum
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16 years ago

problem with the voltage of the output pin

I have used the CPLD for my project. And the device is EPM7128STC100-10(Max7000 series ) ,the voltage of Vccio is 5v,but the output voltage of the I/O is 3.16v. I have defined the I/O standard a...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

It's a valid TTL high level (>2.4V), and according to the MAX7000 datasheet, it's normal operation. The specification is Voh > 2.4V @ Ioh = -4mA, although the typical current capability is higher according to the diagram. But if you havn't any intentional load connected to the pin, you may want to check what's going on in your circuit.