OK to put in 5V TTL into a LVTTL devices

Hi all,

I'm using an NI 9402 (spec PDF here) in a cRIO which says it has LVTTL input (low voltage TTL, seems like 'high' is 3.3V) but maximum input voltage is 5.5V. Would it hurt to use a 'standard' TTL - customer says they have TTL on a BNC, which I think means 0.8V is low, and 5V is high. Maybe my issue is the 9402 says 0.8V is the maximum 'low'.

If not, I'd imagine I can just use a voltage divider or a COTS part?

Thanks! I'm more of a digital weenie - I just don't want to break this nice card

- Rick