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MFerr15's avatar
MFerr15
Icon for New Contributor rankNew Contributor
7 years ago
Solved

Hi, I´m using a Cyclone 10 (10CL040YU484I7G) in a new design can I pull-up this pins CRC_error and INIT_DONE to a 5V rail

INIT_DONE is a open-drain and in the Pin connection guidelines says that "When using this pin, connect it to an external 10-KΩ pullup resistor to an acceptable voltage for all devices in the cha...
ak6dn's avatar
ak6dn
Icon for Regular Contributor rankRegular Contributor
7 years ago

Absolute Vi max for this family is 4.2V for pins, so the simple answer is no you cannot connect these pins to 10K pullups to 5V without causing possible device damage.

You will need some circuitry (diodes, resistive divider, voltage conversion buffer) to connect your 5V device input to what is basically a 3.3V compatible I/O.

Depending on your 5V device technology a pullup to 3.3V may, or may not, produce an acceptable high level. If it is 5VTTL, yes; if it is 5V CMOS, likely not.

Google '3.3 v to 5v level conversion circuit' there are lots of documented ways to do this with both off the shelf devices or discrete circuit components.