National Semiconductor ( NSM) bested Wall Street estimates for sales and earnings, helped by above-normal demand in the PC and wireless markets.

The results were released during Thursday's trading session; National Semi shares were recently up $1.78, or 4.7%, to $39.98.

The chipmaker posted a profit of $93.1 million for the third quarter of fiscal year 2004, up from a loss of $36.4 million a year ago.

The third-quarter results included a $1.9 million pretax credit related to prior cost reductions. Without the credit, net income would have amounted to $91.5 million or 47 cents a share.

Sales of $513.6 million rose 27% from year-ago levels.

Analysts had been expecting a pro forma profit of 41 cents a share on revenue of $496.2 million.

"National's sales into the PC and wireless handset markets were better sequentially than we usually see at this time of year," said chief executive officer Brian Halla in a prepared statement. "Beyond those markets, demand in general for National's analog products picked up during the quarter, particularly in power management, and that's translating into growth in sales and profits."

National guided for sales in the quarter now underway to grow 7% to 10% sequentially. The Multex consensus estimate calls for earnings of 45 cents on sales of $523 million in the quarter.

National also announced today that its board of directors has okayed a share buyback of up to $400 million, following the completion of a similar $400 million buyback black that was completed in October of 2003.

At the close of the third quarter, which ended Feb. 29, the company had 179.4 million shares of common stock outstanding.