Federal Circuit Affirms PTAB Obviousness Finding in DRAM Data Path Patent

In Netlist Inc. v. Micron Technology Inc., No. 2024-1707 (Fed. Cir. Sept. 2, 2026), the Federal Circuit affirmed the PTAB’s finding of unpatentability for  U.S. Patent No. 10,949,339.

Samsung filed an IPR seeking to invalidate Netlist’s patent directed to selectively enabling data paths through a data buffer between a memory controller and DRAM device. In its final written decision, the Board found that Netlist’s patent was obvious over prior art and the general knowledge of a skilled artisan.

On appeal, The Federal Circuit affirmed the Board’s findings. The Court rejected Netlist’s position that the primary reference did not teach selectively enabling data paths. Although the Board relied on a background reference not asserted in any ground of Samsung’s petition to fill a missing limitation, the Court held that any potential error was harmless because the Board alternatively found the limitation taught by the primary reference alone. The Court further rebuffed a series of challenges to the Board’s mapping of “data paths” onto the prior art, crediting Samsung’s expert testimony and inconsistencies within Netlist’s own claim mapping. Finally, the Court rejected Netlist’s APA allegations that the Board merely “summarized Samsung’s ‘contentions’ and [found] that Netlist ‘does not dispute’ them,” holding that Netlist failed to raise this argument with proper specificity.