Forum Discussion
Altera_Forum
Honored Contributor
17 years agoThe Max II handbook is giving detailed answers to all questions raised here. There is particularly a paragraph titled multivolt i/o interface.
1. Max II clearly isn't 5 V tolerant. 2. TTL inputs can be driven from MAX II banks with VCCIO of 3.3V (3.3V LVCMOS I/O standard) without level translation. 5V CMOS logic needs level translation, cause minimum Vih can't guaranteed. 3. To drive MAX II from 5V-logic, you can use voltage dividers, series resistors with clamp diodes (for some MAX II inputs, internal pci clamp diodes can be activated) or level translation.