The U.S. Department of Justice (DoJ) probe into the static RAM (SRAM) chip market appears to be widening.\n\n\n\n\n\n\n\n\n\nSony HeadquartersSony said Tuesday that its U.S. unit, Sony Electronics, has received a subpoena from the DoJ seeking information on its SRAM business. In a brief statement, the company said it will cooperate with the request.Earlier this month, four other SRAM companies said they had also been contacted by the DoJ. They are Cypress Semiconductor, which was first to announce it had been contacted, and the U.S. units of Mitsubishi Electric, Samsung Electronics and Toshiba.SRAM is typically used as a memory buffer in devices such as computers and hard-disk drives. It can retain data as long as power is supplied. That puts it between dynamic RAM, which retains data with power but requires refreshing, and flash memory, which retains data even when power is not supplied.The nature of the DoJ\u2019s requests\u00a0is unclear.-Martyn Williams, IDG News Service (Tokyo Bureau)Related Links:\n\nMitsubishi SRAM Sales Probed by U.S. DoJ\n\nU.S. Extends SRAM Antitrust Probe to Samsung\n\nSRAM Industry Probe Hits Toshiba\n\nSamsung Execs Plead Guilty in DRAM CaseCheck out our CIO News Alerts and Tech Informer pages for more updated news coverage.