SOUTH PORTLAND, Maine — Top Texas Instruments executives were in South Portland this week, meeting with their new employees, acquired through the purchase of National Semiconductor.

The $6.5 billion deal closed Friday, almost six months since it was announced. The South Portland plant is one of the city’s largest employers, with 550 workers. Kevin Ritchie, Texas Instruments’ senior vice president and manager of worldwide technology and manufacturing, told Maine reporters Tuesday the company had no plans to close the South Portland facility or to cut jobs here or in other manufacturing areas as part of the acquisition.

“The desire is to do more together, faster,” said Ritchie. “We’re not looking at shutting things down.”

Ritchie did say there has been overlap in the sales, administration and general support areas of the company. Roughly 5 percent of National’s 5,700 work force — or about 285 people – either were let go as of the close of the deal, or will be within a year. Those people already have been told about this, said Ritchie, and none of them work at South Portland’s plant.

Ritchie said the goal is to double National’s annual revenues of about $1.4 billion within eight quarters.

The two companies make analog chips which are widely used in electronics to transform signals such as sound into digital form that computers can understand.

Stephen Anderson, senior vice president and world manager of high-performance analog at TI, noted that the company owned about 14 percent of the highly fragmented $42 billion analog market last year, while National Semiconductor owned about 3 percent.

“We have 83 percent to go,” he said.

TI’s largest competitor in the analog space is STMicro, which has about 8 percent market share.

At least at first, the South Portland plant will continue to produce the same chips it has been working on. But as the company examines its new capabilities, the Maine plant may begin running more TI products. A number of TI customers would like to see a second plant producing certain types of chips, Ritchie said.

Texas Instruments and National Semiconductor, two of the world’s biggest makers of analog chips, previously had been longtime rivals.

“It was kind of a shocking development for people that watched the industry for a long time, TI buying National — an old Silicon Valley company,” said Rob Lineback, a senior market research analyst with IC Insights of Scottsdale, Ariz.

Lineback questioned whether TI would keep open all the manufacturing facilities that had once belong to National. In the 2008-2010 time frame, TI made several purchases to expand capacity, picking up factories in China, Japan and the Philippines. The company also equipped a factory in Richardson, Texas, with advanced, 300 millimeter manufacturing technology.

“It just looks like to me they are probably going to have to make a decision about how many facilities to keep going,” he said, though he added that he couldn’t see TI shuttering the South Portland plant.