In a mid-quarter update issued after markets closed Tuesday, the Dallas-based company said earnings would come in between 49 cents and 53 cents per share on revenue between $3.56 billion and $3.72 billion.

That would be in the higher end of a range of 46 cents to 52 cents per share on revenue between $3.49 billion and $3.79 billion, which Texas Instruments predicted when it released second-quarter earnings in July.

The revised forecast included a 2-cent-per-share gain from the July sale of a semiconductor product line associated with DSL equipment.

Analysts polled by Thomson Financial expected earnings of 49 cents per share on revenue of $3.66 billion for the quarter ending Sept. 30.

Cody Acree, analyst with Stifel, Nicolaus & Co., said he was encouraged by continued strength in the company's analog sector. "It's good to see but it's not surprising," he said.

Investors, however, sent shares tumbling 77 cents, or 2.2 percent, in after-hours trading Tuesday. Before the new forecast was released, shares rose 50 cents to close at $35.72.

So far, the biggest growth area for the quarter has been in high performance analog chips used in cell phones and a variety of other electronic gadgets, said Ron Slaymaker, TI's vice president for investor relations.

But he was less clear on demand for wireless chips sold to struggling handset makers such as Motorola Inc., calling the sector "mixed."

The company's semiconductor business should see revenue between $3.36 billion and $3.50 billion, compared with the previous range of $3.29 billion to $3.57 billion, TI said.

The relatively small education technology division would be unchanged, with revenue coming in between $200 million and $220 million, Slaymaker said.

The update came a day after Texas Instruments detailed plans to lay off 191 workers whose manufacturing jobs in Dallas are being eliminated and who couldn't find other positions at the semiconductor company.

The layoffs will begin in early November and be spaced out until the end of January, the Dallas-based company said. The workers will be put on paid leave for 60 days after their release, the company said.

Texas Instruments is also finishing the last of 233 layoffs from two other facilities in Dallas by year end.