Integrated Circuit Systems, Inc(ICS) is an industry leader in the design, development, and sales of clock devices for communications, networking, computing, and digital multimedia applications. The company is headquartered in Norristown, Montgomery County, USA, and has factories in San Jose, California, Tempe, Arizona, Worcester, Massachusetts, and Singapore.

In 2005, Integrated Device Technology (IDT), a world-renowned supplier of communication integrated circuits, announced that it would acquire Integrated Circuit Systems (ICS) for US$1.7 billion. Through the acquisition, IDT will further expand the market for chip production.