Microsemi
Former American semiconductor supplier focused on high-reliability, analog, mixed-signal, power, timing, communications, and programmable-logic products.
Last updated August 22, 2026
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Overview
Microsemi Corporation was an American semiconductor and systems company headquartered in Aliso Viejo, California. Its products served aerospace and defense, communications, data-center, industrial, medical, security, and space applications. The company developed and supplied high-performance and radiation-hardened analog and mixed-signal integrated circuits, discrete semiconductor components, power-management devices, timing and synchronization products, field-programmable gate arrays, system-on-chip products, application-specific integrated circuits, radio-frequency components, Ethernet and Power-over-Ethernet solutions, voice-processing devices, storage and communications products, and security technologies. The business began in February 1959 in Culver City, California, as MicroSemiconductor. It incorporated in Delaware in 1960 and initially built a business around miniature silicon diodes and other semiconductor components, with substantial exposure to military and aerospace customers. During the 1960s its products were associated with defense electronics, missile systems, radiation measurement, and miniaturized electronic assemblies. The company later expanded its manufacturing and product scope, moved to Santa Ana in 1972, and adopted the Microsemi name in 1983. Under Philip Frey Jr., who took leadership of the company in the early 1970s, Microsemi grew from a small defense-oriented supplier into a larger semiconductor acquisition platform. A 1987 convertible-debt offering supported a series of acquisitions, many of which later proved difficult to integrate or operate profitably. Microsemi subsequently sold or closed non-core businesses and refocused on semiconductor products. It became publicly traded on Nasdaq in 1990. The company also developed international manufacturing and engineering operations, including packaging activities in Taiwan, a high-reliability facility in Ennis, Ireland, and a joint venture in China. The company entered a more extensive acquisition phase in the 2000s and 2010s under James J. Peterson. It acquired businesses covering space and high-reliability components, defense and security, power management, radio frequency, communications, Ethernet, timing, programmable logic, and mixed-signal design. Notable additions included Linfinity, Actel, Symmetricom's timing business, Zarlink, Vitesse, PMC-Sierra, and the Vectron timing business. These transactions helped position Microsemi as a diversified supplier for mission-critical electronics rather than only a maker of discrete defense components. Microsemi emphasized long-life, high-reliability products for demanding environments. Its devices were used in aerospace and space programs, including systems associated with the Mars Curiosity rover landing, as well as launch systems, avionics, telemetry, navigation, mission computers, cameras, and other instruments. The company also supplied commercial infrastructure markets such as data centers, wired and wireless communications, enterprise storage, and industrial control. Microchip Technology announced in March 2018 that it would acquire Microsemi for approximately $10 billion. The transaction received regulatory clearance and was completed in May 2018. Microsemi therefore ceased to operate as an independent publicly traded company, while many of its product families, technologies, and operations continued within Microchip Technology.
History
Microsemi originated as MicroSemiconductor in Culver City, California, in February 1959. The company incorporated in Delaware on September 27, 1960. Its early business centered on miniature silicon diodes and related semiconductor components for military, aerospace, scientific, and industrial electronics. Contemporary technical references associated the company with diode applications in the Improved Minuteman program, radiation measurement, and miniaturized electronic assemblies. In 1969, MicroSemiconductor merged with Standard Resources Corporation after a proposed transaction disclosed significant ownership by Arthur Feldon, Steve Manning, and Thomas C. Hall. In 1971, the company's New York operation was spun off and Philip Frey Jr. joined from Teledyne's semiconductor division to lead the business. Microsemiconductor moved from Culver City to Santa Ana in 1972. The company remained heavily dependent on defense customers, but its sales and product portfolio expanded during the 1970s and 1980s. JemKap acquired a substantial interest in the company in 1982, and Microsemiconductor acquired the Siemens Components Group in Scottsdale, Arizona. The company changed its name to Microsemi in February 1983. It raised capital through public stock and convertible-debt offerings during the 1980s, using part of the proceeds to acquire numerous businesses. The acquisition program strained profitability, prompting a restructuring beginning in 1989. Microsemi sold or closed several non-core subsidiaries and returned its attention to semiconductor products. Its shares moved from over-the-counter trading to Nasdaq in March 1990. Microsemi internationalized its operations during the early 1990s. It established packaging joint ventures in Taiwan, acquired an Ennis, Ireland, facility in 1992, and formed a majority-owned joint venture in China in 1994. It also acquired Unitrode's semiconductor products division in 1992. Financial pressure was evident in 1993, when the company's stock fell sharply amid a cash crunch and restructuring charges related to defense-budget reductions and the disposal of unrelated businesses. Linfinity became Microsemi's first integrated-circuit company acquisition in 1999. James J. Peterson, previously Linfinity's president, became Microsemi's president and chief executive in November 2000. The company relocated its headquarters to Irvine in 2001 and then to Aliso Viejo in 2011. Under Peterson, Microsemi pursued a broad acquisition strategy. Between 2006 and 2010 it added companies and product lines in space and high-reliability electronics, defense and security, power management, RF, communications, data-center infrastructure, programmable logic, and analog mixed-signal design. Acquisitions included Actel, Advanced Power Technology, PowerDsine, Symmetricom-related assets, Zarlink, Vitesse, and other specialist suppliers. Microsemi expanded its timing portfolio through the acquisition of Maxim Integrated's timing business and Symmetricom-related assets, and broadened communications and data-center capabilities through acquisitions including Centellax, Vitesse, and PMC-Sierra. In 2013, Paul Pickle was promoted to president and chief operating officer while Peterson retained the chief executive role and became chairman. Microsemi also established a Cork design group through the acquisition of Mingoa, which focused on system-on-chip software and ARM-oriented designs. The company began divesting selected businesses in 2016, including defense-focused units acquired during the previous decade and its broadband wireless division. In 2017 it agreed to acquire the Vectron International timing business from Knowles. By this point Microsemi presented itself as a provider of semiconductor and system solutions for aerospace and defense, communications, data centers, and industrial markets. Its products were used in space and mission-critical systems, including applications associated with the Mars Curiosity rover and with launch, avionics, telemetry, navigation, control, computing, and imaging. Microchip Technology announced an agreement to acquire Microsemi for approximately $10 billion in March 2018. The acquisition was completed in May 2018. Microsemi consequently ceased to be an independent listed company, although its technologies and product families were incorporated into Microchip's business.
- 2018
Acquired by Microchip Technology
[1]Microchip Technology completes its approximately $10 billion acquisition of Microsemi in May.
- 2016
Selected business divestitures announced
[1]Microsemi announces the sale or divestiture of defense-focused units and its broadband wireless division as part of portfolio rationalization.
- 2011
Headquarters moves to Aliso Viejo
[1]Microsemi relocates its headquarters to Aliso Viejo, California.
- 2001
Headquarters moves to Irvine
[1]The corporate headquarters relocates from Santa Ana to Irvine, California.
- 2000
James J. Peterson becomes chief executive
[1]Peterson, formerly president of Linfinity, is promoted to president and chief executive.
- 1992
Irish operations established
[1]Microsemi acquires a facility in Ennis, County Clare, supporting high-reliability semiconductor development, manufacturing, and testing.
- 1990
Listing moves to Nasdaq
[1]Microsemi begins trading on the Nasdaq exchange after previously trading over the counter.
- 1983
Microsemi name adopted
[1]Microsemiconductor changes its corporate name to Microsemi.
- 1972
Headquarters moves to Santa Ana
[1]The company relocates from Culver City to Santa Ana, California.
- 1960
Delaware incorporation
[1]MicroSemiconductor incorporates in Delaware on September 27.
Products and positioning
A specialist semiconductor supplier for high-reliability, mission-critical, and infrastructure applications, combining defense and space heritage with analog, power, timing, communications, security, and programmable-logic technologies.
Aerospace and defense semiconductors
High-reliability and radiation-hardened semiconductors
Microsemi supplied semiconductor devices designed for demanding aerospace, defense, satellite, and space environments. These products emphasized reliability, long operating life, resistance to radiation, and qualification for mission-critical applications. They supported launch systems, avionics, telemetry, navigation, mission computers, drive control, cameras, and scientific instruments.
Programmable logic
ProASIC FPGA family
The ProASIC family consisted of flash-based field-programmable gate arrays for embedded, industrial, communications, security, and other applications. The family was associated with nonvolatile configuration and security-oriented use cases. ProASIC3 devices later became the subject of security research concerning factory testing credentials and differential power analysis.
Programmable logic
PolarFire FPGA
PolarFire was a lower-power FPGA family aimed at communications, industrial, defense, and embedded applications. It was recognized as a 2017 Product of the Year by Electronic Products China and 21ic.com, with the recognition reported in 2018.
Power semiconductors
Power-management products
Microsemi's power portfolio included power-management integrated circuits, discrete power devices, and Power-over-Ethernet components. These products addressed industrial equipment, communications infrastructure, enterprise systems, defense electronics, and other applications requiring power conversion, distribution, protection, or control.
Timing semiconductors
Timing and synchronization solutions
Microsemi developed precise timing, clock-generation, synchronization, and frequency-control products for telecommunications, data centers, networking, industrial systems, and aerospace applications. Acquisitions involving Symmetricom and Vectron expanded the company's capabilities in precision timing and timing infrastructure.
Radio-frequency semiconductors
RF and microwave products
The company supplied RF transceivers, microwave components, and related solutions for communications, defense, aerospace, and instrumentation. Its portfolio was expanded through acquisitions such as Spectrum Microwave and Centellax.
Communications semiconductors
Ethernet and communications solutions
Microsemi provided Ethernet controllers, switching and connectivity products, Power-over-Ethernet integrated circuits, storage and communications solutions, and related infrastructure technologies. These products served enterprise networks, data centers, telecommunications equipment, and industrial communications.
Controversies
2018
Pre-acquisition discounting and spending concerns
After closing the acquisition, Microchip reported concerns that Microsemi had shipped large distributor orders at discounted prices before the transaction and had a culture of excessive extravagance.
2012
ProASIC3 factory-key security controversy
Researchers reported a differential-power-analysis technique that could extract an undocumented factory encryption key from ProASIC3 devices. Microsemi denied that the feature represented an intentional backdoor but acknowledged a factory passcode used for testing and stated that the issue reflected a broader risk to FPGA manufacturers.
2009
James Peterson academic-credential controversy
A report questioned academic degrees listed in James Peterson's biographical materials and regulatory-related filings. After an independent investigation, Microsemi said he had not earned the claimed degrees. Peterson paid a fine to the company and forfeited his 2008 bonus.
Marketing campaigns
- 2012Microsemi Ireland 20th anniversary and engineering education program
Ireland · Europe
To mark two decades of Irish operations, Microsemi designated Ennis as its European headquarters, launched an engineering scholarship at the University of Limerick, and supported a science and aerospace engineering program at St. Flannan's College.
Outcome. The initiative reinforced Microsemi's presence in Ireland and its relationship with local education and investment agencies.
Brand decisions
2018
Accept acquisition by Microchip TechnologyM&ABackground
Microchip Technology sought to expand its portfolio in analog, power, timing, communications, aerospace, defense, and high-reliability semiconductors.
Action taken
Microsemi agreed to be acquired by Microchip Technology in a transaction valued at approximately $10 billion.
Aftermath
The acquisition closed in May 2018, ending Microsemi's independent public-company status and integrating its operations and product families into Microchip.
Transaction value. Approximately $10 billion (2018)
2017
Acquire Vectron International timing businessM&ABackground
Microsemi wanted to expand its precision timing and frequency-control portfolio for communications, data-center, industrial, and aerospace customers.
Action taken
It announced the acquisition of the Vectron International timing business from Knowles.
Aftermath
The transaction strengthened Microsemi's position in precision timing products.
Acquisition price. $130 million (2017)
2016
Divest selected defense and broadband wireless businessesStrategyBackground
Following years of acquisition-led expansion, Microsemi reviewed its portfolio and determined that certain businesses were not central to its strategic priorities.
Action taken
The company announced divestitures of defense-focused units acquired between 2009 and 2011 and sold its broadband wireless division for $21 million.
Aftermath
The divestitures narrowed the portfolio around semiconductor and infrastructure businesses that management considered more strategically aligned.
Broadband wireless division sale price. $21 million (2016)
2006
Broaden the company through specialist semiconductor acquisitionsStrategyBackground
Microsemi sought to reduce dependence on a narrow defense-component market and build a broader platform for high-reliability, communications, power, security, and industrial electronics.
Action taken
The company acquired businesses in space electronics, defense, security, power management, RF, communications, timing, programmable logic, and analog mixed-signal design.
Aftermath
Microsemi became a diversified semiconductor supplier with exposure to aerospace, data centers, communications, industrial systems, and mission-critical electronics.
1989
Restructure and exit non-core subsidiariesStrategyBackground
A large acquisition program undertaken during the 1980s strained profitability, while defense-budget reductions weakened the company's traditional customer base.
Action taken
Microsemi began selling or closing subsidiaries outside its core semiconductor business and recorded restructuring-related write-offs.
Aftermath
The company refocused on semiconductor products and returned to growth after the restructuring period.
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