On Semiconductor has signed a definitive agreement to acquire Aptina Imaging, a provider of CMOS image sensors for automotive and industrial markets, for approximately $400 million in cash. The transaction is expected to close during the third quarter of 2014.

Phil Carmack has joined Aptina as CEO and as a member of the board. Mr. Carmack succeeds Nicholas Brathwaite, who has been Aptina’s Interim...