Convert TTL to LVTTL

[matchstick86]

Hola.
I am trying to convert a 5V TTL down to a 3.3V LVTTL. This is an ex-Physics ex-student asking. Any clue?

[MATLABdude]

Are you just looking to replace one part in your existing unit, or change a design?

If replacing one part, I'd get the right (5V) part.

If changing your design, can you convert the rest of your system to 3.3V? even if not, you might be able to get away with outputting 3.3V to 5V inputs (check the datasheets) and use voltage dividers to reduce 5V inputs to 3.3ish V.