The US Department of Justice (DoJ) has started an anti-trust investigation into the SRAM (static random access memory) market, which produces chips used to store data in low-power devices such as mobile phones.

One company involved is Cypress Semiconductor, which said in a statement yesterday it plans to support the investigation by sharing access to its employees and documents.

Federal investigators contracted Cypress on Wednesday night and asked for documents, said spokesman Joseph McCarthy. He did not know whether investigators had also reached other vendors.

"We assume the DoJ is looking at the market and the practices involved," McCarthy said. But he cautioned that it was too early to draw parallels to the ongoing investigation of manufacturers of dynamic random access memory (DRAM).

The DoJ brought charges in September against the DRAM vendor Samsung for global price-fixing in the sale of memory chips to PC makers including Apple, Dell and HP. Other companies charged with related actions include Infineon and Hynix. In July, 34 states brought an anti-trust lawsuit against seven DRAM vendors for similar price-fixing practices.

In a separate investigation, the Federal Trade Commission (FTC) said in August that Rambus had run an illegal monopoly in the market for DRAM memory chips by inserting its own technology into a common standard without disclosing that it had already patented the method. Rambus later sued producers of the standard for licensing fees.

Cypress' SRAM chips are used in networking equipment such as switches and routers, IP phones and automotive electronics, and the company's low-power SRAM is used in mobile phones, PDAs, handheld radios and gaming platforms.