Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 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
Icon for Honored Contributor rankHonored Contributor
16 years ago

--- Quote Start ---

I would ask support, if they can tell what exactly happens in this situation and if there's a risk of either device damage or temporary functional failure. I fear, you don't get a satisfying answer.

Frank

--- Quote End ---

I filed a service request and the answer was only partly satisfying.

There is a kind of multivoltage I/O application note for Cyclone III and IV.

It is AN447 (http://www.altera.com/literature/an/an447.pdf) (http://www.altera.com/literature/an/an447.pdf%29). This application note however is limited to 2.5V, 3.0V and 3.3V I/O.

Although I try to push him a bit, the application engineer advices to keep the input voltage below te recommended Vih,max.

An overshoot voltage of 3.95V can be applied for 100% of the time over a 10 year period.

I don't get any statement about what happens when I drive the input with a voltage between Vih,max and Vovershoot.

Regards, Ton