Microsemi Corporation was an Aliso Viejo, California-based provider of semiconductor and system solutions for aerospace & defense, communications, data center and industrial markets.

In February 2018, it was announced that Chandler, Arizona-based Microchip Technology was acquiring the company for over US$10 billion, pending regulatory approval.

[8] In March 1963, A. Feldon represented Microsemiconductor Corp in the Advisory Panel of Suppliers at the IEEE session on "Components for Miniaturized Electronic Assemblies".

[citation needed] On August 13, 1969, Standard Resources Corporation, from Copiague, New York, a close-end management investment company, filed at the U.S. Securities and Exchange Commission a request to merge with Microsemiconductor.

Kaplan's JemKap Inc owned 37.7% of the outstanding common shares of Standard, which would make him the owner of 18.9% of the surviving company.

[14] Source:[15] According to the Orange County Business Journal, "In 1971, the New York operation was spun off and Philip Frey Jr. was brought on from Teledyne Inc.'s semiconductor division in Hawthorne to head Microsemiconductor.

When the acquisitions began straining profitability, Frey didn't waste a lot of time admitting his mistake.

[19] On March 9, 1986, Microsemi, at the time a supplier of "high-performance semiconductor diodes in a variety of military, industrial and commercial products", issued 2.5 million shares of common stock.

The Ennis facility's key competencies are the development, manufacturing and high reliability testing of semiconductors to meet stringent aerospace, satellite, medical and security standards.

In 1989, the company said it planned to sell or close 10 subsidiaries not related to its core business of manufacturing computer chips for use in electronics equipment ranging from military weapons to heart pacemakers.

In addition, the company funded a high-profile science and aerospace engineering programme in St. Flannan's school in Ennis.

[42][43] Microsemi has provided semiconductor solutions for numerous U.S. space programs dating back to the launch of the first Atlas rocket.

[44] Source:[45] In 2009 Barry Minkow, co-founder of the Fraud Discovery Institute, published a report claiming that James Peterson, Microsemi's president and CEO, had not obtained a bachelor's degree or Master of Business Administration as he had listed on his biography on STEC Inc.’s regulatory filings (as part of his board position with that company) and on a US government security clearance application.

The next day, the registrar of Brigham Young University advised that they had double-checked and had no records of Peterson ever having obtained any degrees.

An independent inquiry was made on behalf of the board by the law firm Munger, Tolles & Olson, which confirmed that in fact Peterson had not earned either degree.

[116] Microsemi was headquartered in Aliso Viejo, California and had offices in California (Camarillo, Cupertino, Garden Grove, San Diego, San Jose, Santa Clara, Santa Rosa); Boulder, Colorado; Atlanta, Georgia; Beverly, Lawrence, and Lowell, Massachusetts; Allentown and Reading, Pennsylvania; Austin and Dallas, Texas; Ottawa, Canada; Macau, Shanghai and Shenzhen, China; Herlev, Denmark; Bruges, Belgium; Ennis, Ireland; Hod HaSharon, Israel; Manila and Cabuyao, Philippines; Caldicot, United Kingdom; and Hyderabad, India.