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Altera_Forum
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15 years ago

VCCIO Voltage Change

Hi, I use EP3C10F256C8 chip , VCCIO set 1.8V , if other IO pin input set Hi(3.3V), result VCCIO change 2.2V? VCCIO set 1.5V , if other IO pin input set Hi(3.3V), result VCCIO change 2.2V?
Altera_Forum's avatar
Altera_Forum
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15 years ago

I also couldn't clearly understand the question, but some above told assumptions are wrong. Particularly, Altera FPGAs don't have substrate diodes between I/O pins and any supply voltage. So it's always safe to overdrive an I/O pin with a higher logic voltage, of course paying attention to the maximum ratings. The input thresholds are expected to change with VCCIO, however.