Elysian Fields Sues Renesas on Three Semiconductor Patents Over Microcontrollers and R-Car Chips.

The case

The case is Elysian Fields Technologies LLC v. Renesas Electronics America Inc., No. 2:26-cv-00962 (E.D. Tex., Marshall Division), assigned to Judge Rodney Gilstrap. The complaint is signed by Trevor J. Beaty of Shea Beaty Poet PLLC in Sherman, Texas. It describes Elysian Fields as a Texas limited liability company with a place of business in Plano, Texas, and alleges, on information and belief, that Renesas Electronics America is a California corporation with a place of business in Plano. Venue is pleaded under 28 U.S.C. 1400(b).

The three patents

U.S. Patent No. 6,331,953, titled Intelligent Ramped Gate and Ramped Drain Erasure for Non-Volatile Memory Cells, issued December 18, 2001. Claim 23, the asserted claim, covers a method of erasing a memory cell that has two regions with a channel between them, a gate above the channel, and a charge trapping region. The method applies a voltage across the gate and the first region in a coarse erase sequence of voltages and in a fine erase sequence of voltages, each removing a portion of the trapped charge. The complaint says the patent expired on November 10, 2020.

U.S. Patent No. 6,831,346, titled Buried Layer Substrate Isolation in Integrated Circuits, issued December 14, 2004. Claim 1 covers an integrated circuit with a transistor formed in a well region of the same conductivity type as the substrate, and a buried layer below the well of the opposite conductivity type. The buried layer has a central portion under the transistor and a separate annular portion, spaced apart from it, that surrounds it. The complaint says the patent expired on December 10, 2021, and describes the problem it addresses as substrate coupled noise from switching transistors reaching analog circuitry on the same die.

U.S. Patent No. 8,564,605, titled Display Interface Buffer, issued October 22, 2013. Claim 1 covers a device with a general purpose memory holding display data, several display drivers that each drive a different portion of a panel, a direct memory access controller that moves data from the memory to the drivers, and transaction descriptors reflecting a display memory map. Each descriptor directs the controller to the data, associates contiguous destination addresses identifying the drivers with noncontiguous source addresses in memory, and identifies the size of the data to be accessed. Google Patents lists the '605 patent as expired for failure to pay maintenance fees, with the lapse effective October 22, 2025. USPTO assignment records show all three patents assigned to Elysian Fields by an assignment executed May 5, 2026 and recorded May 6, 2026.

What is accused

For the '953 patent, the complaint accuses, on information and belief, Renesas devices with embedded nonvolatile flash memory, including devices bearing R5F6 series part numbers and other microcontrollers using substantially similar flash memory technology. Exhibit A-1 charts claim 23. For the '346 patent, it accuses, also on information and belief, devices in the RH850/F1x series, including the RH850/F1L product line, which it says incorporate embedded flash memory, with Exhibit B-1 charting claim 1. For the '605 patent, it accuses, on information and belief, the R-Car E2 and R-Car E3 families of automotive systems on chip used in instrument clusters, display audio systems and integrated cockpits, with Exhibit D-1 charting claim 1. The exhibits are not on the public docket.

The counts and the knowledge allegations

Count I ('953), Count II ('346) and Count III ('605) each allege, on information and belief, direct infringement (35 U.S.C. 271(a)), induced infringement under 35 U.S.C. 271(b), and contributory infringement under 35 U.S.C. 271(c). For the two patents it says have expired, the complaint asserts liability only from October 23, 2020 to each patent's expiration. It alleges that Renesas was made aware of the '953 and '346 patents at least as early as August 7, 2018, when it received correspondence from the prior owner stating that Renesas had been made aware of the patents and presented with claim charts, and it alleges willful infringement of both. For the '605 patent, it alleges that Renesas received correspondence from the prior owner identifying the patent and representative products at least as early as March 1, 2022, alleges willfulness since that date, and alleges that the accused products infringed and continue to infringe.

The relief sought

Elysian Fields asks for a judgment that Renesas infringed all three patents; damages for past infringement of the '953 and '346 patents with interest, costs and an accounting; damages for past and continuing infringement of the '605 patent through judgment; a declaration that the case is exceptional with attorney fees under 35 U.S.C. 285; and other relief. It demands a jury.