The American corporation International Rectifier has invested £25m in the project at Penllergaer near Swansea.
International Rectifier is said to be the world's fastest growing semi-conductor company.
It produces advanced control modules used in everything from mobile phones to satellites.
The possiblity of linking up with researchers at Swansea University's electronics department was one factor which helped clinched the deal, said the Welsh Development Agency's vice chairman Sir John Allen.
He said the investment brought cutting edge technology and highly skilled jobs to Wales.
Assembly Economic Development Secretary Rhodri Morgan, who officially opened the plant, said the company's arrival was the culmination of several years of detailed and determined negotiation.
The chief market for the company is the motor industry.
The firm claims that every car on Earth contains at least £6 worth of its parts.
Ambitious plans
The company wants that figure to grow to £30 and its new factory in Swansea is part of the ambitious expansion plan.
The high technology production techniques mean many of the new jobs are highly skilled.
The firm has embarked on an extensive recruitment drive for the new factory.
It will also provide much-needed investment to west Wales.
International Rectifier is the oldest semi-conductor company in the world - founded in California in 1947.
It employs 3,500 people worldwide with factories in the USA, Mexico, Italy and the UK.
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Swansea Council
Welsh Development Agiency
International Rectifier
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