National Semiconductor ( NSM) said Wednesday that it plans to restructure its operations and take a fourth-quarter charge. The chipmaker said it will cut some 340 jobs and close a division that makes cell-phone components, which will result in a charge of $25 to $30 million in the fourth quarter. The company also is considering the sale of its information-appliance unit. "We are moving quickly to execute our plans to provide higher returns sooner to shareholders," said the company's chairman, president and chief executive, Brian L. Halla, in a company statement. National Semiconductor estimates the restructuring will promote savings of $30 million per quarter, or $120 million annually. The company doesn't expect the move to affect fiscal fourth-quarter revenue, estimated to come in between $420 and $432 million. The quarter ends May 25. Since the company's third quarter, a total of 840 employees have been laid off, or 8% of National Semi's workforce.