ON Semiconductor, operating under the onsemi brand, announced last week its largest acquisition to date: the takeover of Synaptics in an all-stock transaction with an enterprise value of approximately $7 billion. The goal is to transform onsemi from a supplier of semiconductors and sensors into a broader player in so-called “physical AI”—that is, artificial intelligence embedded directly into machines, vehicles, and devices. Management promises that the merger will expand the company’s addressable market by $30 billion to $243 billion by 2030 and create a leader in this new category.

This analysis examines whether this is a strategically sound move at a reasonable price or an expensive bet on a market that is not yet mature. The question has three layers. First, is the logic behind combining onsemi’s power and sensor businesses with Synaptics’ computing, connectivity, and sensor businesses truly as complementary as management claims? Second, is the $243 billion figure a realistic market…