SANTA CLARA, Calif. – National Semiconductor Corp., which makes analog chips used in cell phones, computers and televisions, said Thursday it is cutting about 550 jobs, or about 6 percent of its global work force, as it copes with an inventory buildup and lower demand.

Thirty people out of a 600-person crew were laid off Thursday at National Semiconductor’s South Portland design and manufacturing plant, according to spokesman Jeff Weir.

“It’s a far lesser number than at our other plants,” he said. “It’s a very small part of our work force in Maine.

About 450 jobs will be cut at worldwide factories, and another 100 will be eliminated from other parts of the company, including its headquarters. It previously reported a headcount of about 9,000.

“Maine is our newest factory and it’s the most in-demand facility, so the fewest layoffs are there,” Weir said.

In a statement, National said its factories ran about 65 percent of capacity in its fiscal second quarter, down from the mid-90s during most of fiscal 2004. The decline is the result of actions taken to control an inventory glut that affected most chip companies in the second half of 2004.

Brian Halla, the company’s chief executive, said National will focus on higher-end chips and de-emphasize those that carry little profit.

The company said it expects to take a charge of $22 million to $26 million for severance and related expenses. Most of that will be reflected in its fiscal-third quarter results, which will be announced March 10.

Shares of Santa Clara-based National Semiconductor rose 19 cents to close at $17.07 Thursday on the New York Stock Exchange.