The difference is the temperature range, which can be found on page 4 of the datasheet.
- L78LxxAC/L78LxxC: 0...125°C
- L78LxxAB: -40...125°C
Good luck!
If the problem is resolved, please mark this topic as answered by selecting Select as best. This will help other users find that answer faster.
/Peter
In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.