Lifecycle information for Cyclone III EP3C5E144C8N and EP3C16Q240C8N

The present state is active as you see at distributors. If your question targets to the expectable future availability, you need to ask Altera sales or contracted distributors.

Presently, even some first generation Cyclone devices are still in production because there's apparently a demand. Similarly I would expect that the 240PQFP devices which are preferred by some users on low density PCBs have some life expectation. EP3C5E144C8N has a 97% pin compatible Cyclone IV replacement.

Cyclone IV is unique in some features compared to newer Cyclone V, 10 and MAX10 and is planned to be continued according to my distributors. Of course, there can be always reasons to change plans.