Limestone Memory Systems LLC (LMS), a subsidiary of Acacia Research Corporation, sued Apple for alleged infringement of a group of semiconductor patents (5,805,504, 5,894,441, 6,233,181, 6,697,296). The patents-in-suit concern semiconductor memory chips and the programming of those chips; all four have been previously asserted by LMS, including in cases against Acer, Dell, HP, and Lenovo. LMS’s campaign is targeting devices that incorporate DRAM chips manufactured by Micron, including smartphones, tablets, and laptops. Micron was among the first companies LMS sued in this campaign, in February 2015.