Altium Limited is an American multinational software company that provides electronic design automation software to engineers who design printed circuit boards. Founded as Protel Systems Pty Ltd in Australia in 1985, the company has regional headquarters in the United States, Australia, China, Europe, and Japan. Its products are designed for use in a Microsoft Windows environment and used in industries such as automotive, aerospace, defence and telecommunications. Its flagship product, Altium Designer, is a software for unified electronics design. Since August 2024, Altium is a subsidiary of Renesas Electronics.