TOKYO, Feb 15 (Reuters) - Japanese chipmaker Renesas Electronics on Thursday said it will acquire a 100% stake in Australian design software provider Altium for A$9.1 billion ($5.91 billion) in an all-cash transaction.

Renesas will pay A$68.50 per share, putting a 34% premium to Altium's Wednesday closing price, it said in a statement. ($1 = 1.5406 Australian dollars) (Reporting by Kantaro Komiya; Editing by Chris Reese)