Irvine-based Microsemi, a developer of analog and mixed-signal integrated circuits, said this morning that it is buying Actel Corp. in a deal worth $430M. According to Microsemi, it will pay $20.88 per share in cash for Actel. Actel is a supplier of field programmable gate arrays (FPGAs), serving the military, industrial, communications, and consumer markets. Microsemi said the buy would provide it with "compelling synergies". Microsemi has been on an acquisition roll in the last months, and just annoucned last month that it had acquired Arxan Defense Systems and VT Silicon. Microsemi said the acquisition of Actel strengthens its position in the security & defense, commercial aerospace & satellite, enterprise & commercial, and industrial markets.