Unisem to Be Sold for About $50 Million

International Rectifier Corp., a maker of computer chips for power supplies, said Tuesday that it agreed to buy Unisem Inc. in Irvine for about $50 million in cash to expand its line of power-management devices.

Unisem’s analog-based equipment manages power levels of desktop computers, cellular phones and other devices, said International Rectifier spokeswoman Shelley Wagers.

Unisem’s annual revenue is about $32 million. El Segundo-based International Rectifier had $753.3 million in fiscal 2000 sales.

International Rectifier said it expects the acquisition to increase its percentage of revenue from proprietary products and boost earnings within 12 months.

The company’s stock rose $3.81 a share, or 12%, to $35 on the New York Stock Exchange.