National Semiconductor Corp. yesterday said it has agreed to acquire Schlumberger Ltd.'s Fairchild Semiconductor Corp. subsidiary for about $122 million in common stock and warrants.

In selling the ailing semiconductor pioneer to an American-owned competitor, Schlumberger, a French company, avoided exacerbating the political controversy that resulted last year when it tried to sell 80 percent of Fairchild to Japan's Fujitsu Ltd. for about $200 million.

The earlier deal was opposed by Defense Secretary Caspar Weinberger and former Commerce secretary Malcolm Baldrige on the grounds that it would hurt U.S. national security and industrial competitiveness.

"In acquiring Fairchild, National becomes America's best technology-balanced semiconductor supplier," said National's chief executive, Charles Sporck. "This combination will assure a steady stream of leading-edge products for customers... . This consolidation will strengthen the American semiconductor industry as well as National's position in the worldwide marketplace."

Sporck was among the opponents of the sale of Fairchild to Fujitsu.

Most semiconductor industry analysts said the acquisition bodes well for National Semiconductor, based in Santa Clara, Calif. "It's a hell of a good deal," said Mel Phelps, senior technology analyst at Hambrecht & Quist in San Francisco.

"This is a perfect fit with National's production groups," said Jack Beedle, president of IN-STAT, a Scottsdale, Ariz., market research firm. "The key to survival in the semiconductor industry is having more than $1 billion in revenues and being a broad-line manufacturer. This deal will give National both qualities."

Some analysts took a more cautious view. "Fairchild hasn't been a serious competitor for years," said William Milton, technology analyst at Brown Brothers Harriman & Co. in New York. "I don't know what is left there that could be of any value to National."

Fairchild, based in Cupertino, Calif., specializes in technology for mainframe computers. It has annual revenue of between $450 million and $500 million, according to Mona Eraiba, semiconductor analyst at Salomon Brothers Inc. in New York.

Beedle said the the transaction will move National from the nation's fourth-largest semiconductor manufacturer to its third largest, behind Motorola and Texas Instruments. National reported a $25 million loss on sales of $1.9 billion last year, but it posted a small profit in the first quarter of this year.

Analysts said that although National's performance has been relatively lackluster in recent years, it has fared no worse than its competitors in the semiconductor industry. Semiconductors accounted for about 52 percent of National's revenue last year.

Under the agreement, National will acquire all of Fairchild's operations except for wafer fabrication plants in Japan and West Germany. Many analysts say those two plants may have played a big role in Fairchild's poor performance in recent years.

"I would suspect that those plants didn't anticipate the tremendous fall of the dollar. That must have had a heavy impact on them, and if there was any sort of debt associated with them it would be back-breaker," said Beedle.