GENERALLY for IC's except when not...
As expected, TI uses a lot of prefixes with T, like TL, TLC, TLE, THS (excepr for those which they grabbed from BB and NS - and their offspring) and now we find TCA..
So the TCA965 and the TDB555 are TI? Nope - ProElectron.
L prefixes (no other letter) are usually used by ST.