Analog chipmaker National Semiconductor ( NSM) beat sales and earnings expectations Friday, but said revenue could see a seasonal drop-off in the quarter now under way.

The company posted revenue of $422 million, above Wall Street estimates of $410 million. Sales were basically flat with the prior quarter and 15% above last year's levels.

Net profit totaled $6.2 million, or earnings per share of 3 cents, for the quarter ending in November, significantly better than the outlook for a loss of 3 cents a share.

In a prepared statement, CEO Brian Halla said this marked the company's third quarter in a row of profitability in a tough market. "Our revenues exceeded the expectations we had at the beginning of the quarter," he said. We did a good job managing our expenses, and continued to improve our product positioning, especially in the wireless market."

National Semi said orders for the quarter had declined 5% due to more cautious inventory management at distributors, but bookings remained 23% above the prior year. Orders picked up in the second half of the quarter, the company said, particularly for PC-related bookings, such as notebooks. Orders also grew for wireless chips, based on demand in the wireless handset market.

Meanwhile, National said it expects sales to be flat to down 5% sequentially in the quarter under way.

"Our third quarter typically reflects a post-holiday seasonal decline in revenues," Halla said. "Although bookings picked up in October and November, it is too early to tell whether that momentum will carry over enough to offset the normal seasonal pattern." Management expects gross margins to slide a little, in light of lower production.

The stock was down 37 cents, or 2.1%, to $17.28 in early afternoon trading Friday.