Greenthread, LLC v. Renesas Electronics America, Inc.

This patent infringement case is part of a broad litigation campaign by a non-practicing entity (NPE) against major players in the semiconductor industry. The plaintiff, Greenthread, LLC, is a Texas-based patent assertion entity (PAE) founded in 2004 that holds patents originally invented by one of its directors, G.R. Mohan Rao. Greenthread does not appear to manufacture products and is focused on monetizing its patent portfolio through litigation. The defendant, Renesas Electronics America, Inc., is the U.S. subsidiary of the Japanese semiconductor giant Renesas Electronics Corporation, a leading global manufacturer of microcontrollers, analog, power, and System-on-Chip (SoC) products for the automotive, industrial, and consumer electronics markets.

Filed in the U.S. District Court for the Eastern District of Texas, a venue known for its experienced patent judges and procedural rules often favored by plaintiffs, the lawsuit accuses Renesas of infringing U.S. Patent No. 11,121,222. The '222 patent, titled "Semiconductor device with graded dopant region and method of manufacture therefor," generally covers a sensor device that incorporates graded semiconductor layers to improve performance. The accused products are Renesas's semiconductor devices, likely including a wide array of microcontrollers, sensors, and power management ICs that allegedly incorporate this patented technology. The case is presided over by Chief Judge Rodney Gilstrap, who manages a significant portion of the district's heavy patent docket.

The case is notable as a single front in a large, multi-defendant assertion campaign Greenthread has been waging since at least 2019 against other major semiconductor companies like Samsung, Intel, ON Semiconductor, and Cirrus Logic. Many of the defendants have challenged the validity of Greenthread's patents at the Patent Trial and Appeal Board (PTAB). For instance, Cirrus Logic successfully invalidated claims in several Greenthread patents, while ON Semiconductor secured a stay of its district court case pending the outcome of its inter partes review (IPR) petitions. This broader context of parallel PTAB challenges and litigation against numerous industry competitors makes the Renesas case a key part of a larger, well-funded intellectual property dispute impacting foundational semiconductor technology.

Case Developments and Disposition

Analyst's Note: Court records and docket reporting services for case number 2:23-cv-00179 in the U.S. District Court for the Eastern District of Texas identify the defendants as OSRAM GmbH, ams-OSRAM AG, and AMS Sensors USA Inc. (collectively, "ams-OSRAM"), not Renesas Electronics America, Inc. Furthermore, the case is not active; it was terminated on April 19, 2024. This contradicts the authoritative case metadata provided for this analysis. The following summary details the key legal developments for the actual litigation under this case number. No records were found of Renesas being a party to this specific action.

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Filing and Consolidation (2023)

• 2023-04-19: Greenthread, LLC filed a patent infringement complaint against ams-OSRAM in the Eastern District of Texas, assigned case number 2:23-cv-00179 and presided over by Chief Judge Rodney Gilstrap. The suit asserted six patents, including U.S. Patent No. 11,121,222, related to semiconductor devices with graded dopant regions.
• Consolidation: This lawsuit was managed as a "member case" within a larger consolidated action, Greenthread, LLC v. OmniVision Technologies, Inc., Lead Case No. 2:23-cv-00212-JRG. This common practice in the district allows for efficient management of discovery and claim construction across multiple defendants sued on the same patents. Other defendants in the consolidated action included Texas Instruments.

Pre-Trial and Discovery

The case against ams-OSRAM did not progress to significant litigation milestones such as a Markman hearing or summary judgment motions. The docket activity primarily involved initial pleadings and discovery matters handled within the framework of the lead case.

Settlement and Dismissal (2024)

• 2024-04-19: The court entered an order based on a joint stipulation by Greenthread and ams-OSRAM to voluntarily dismiss the case. The key terms of the dismissal were:
  • Greenthread's infringement claims against all ams-OSRAM defendants were dismissed with prejudice, meaning Greenthread cannot sue them again on the same patent claims.
  • Ams-OSRAM's counterclaims against Greenthread were dismissed without prejudice.
  • Each party agreed to bear its own attorneys' fees, costs, and expenses.

The case was officially terminated after exactly one year. The terms of any underlying settlement were not disclosed in public court records.

Parallel PTAB Proceedings on the '222 Patent

While Renesas has not been identified as a petitioner, the '222 patent has been subject to significant challenges at the Patent Trial and Appeal Board (PTAB) by other targets of Greenthread's litigation campaign. These parallel proceedings have a direct bearing on the viability of Greenthread's assertion of the patent against any defendant.

• IPRs Filed by ON Semiconductor: Semiconductor Components Industries, LLC (d/b/a onsemi) filed multiple inter partes review (IPR) petitions challenging claims of the '222 patent and the related U.S. Patent No. 10,510,842. These PTAB challenges led the U.S. District Court for the District of Delaware to stay Greenthread's case against onsemi pending the outcome of the IPRs.
• USPTO Director Vacates Invalidity Decisions (2025): In a major victory for Greenthread, the Acting USPTO Director in April 2025 vacated the PTAB's Final Written Decisions in the onsemi IPRs, which had previously invalidated claims. The Director found that the PTAB had improperly denied Greenthread's request for discovery into whether onsemi's petitions were time-barred under 35 U.S.C. § 315(b). Greenthread had argued that onsemi was in privity with Intel, a time-barred party, and should have been allowed to investigate that relationship. The Director remanded the proceedings back to the Board to permit discovery on this critical issue.
• IPRs Filed by Cirrus Logic: Cirrus Logic, Inc., along with other petitioners, has also filed IPRs challenging Greenthread's patents, including the '222 patent. These proceedings are part of a broader, industry-wide pushback against Greenthread's litigation campaign.

As of May 2026, the validity of the '222 patent claims remains contested at the PTAB, with the ultimate outcome of the remanded onsemi IPRs poised to significantly impact Greenthread's entire enforcement effort.

Plaintiff's Counsel of Record

The following attorneys have appeared on behalf of the plaintiff, Greenthread, LLC, in this matter. Based on filings in this and parallel litigation, the legal team is structured with lead counsel from Pra Law, PLLC, and local counsel from Davis, Cedillo & Mendoza, Inc. to meet the district's requirements.

Lead Counsel

• Name: Papool S. Chaudhari

  • Role: Lead Counsel
  • Firm: Pra Law, PLLC (Plano, TX)
  • Note: Chaudhari is frequently listed as lead counsel for Greenthread across its multi-defendant litigation campaign, managing the core legal strategy for asserting its patent portfolio.

• Name: Justin F. Boyce

  • Role: Lead Counsel
  • Firm: Pra Law, PLLC (Plano, TX)
  • Note: A former aerospace engineer with a background in electrical engineering, Boyce has extensive experience litigating patent cases in the semiconductor and computer industries.

Local Counsel

• Name: J. Ricardo Cedillo
  • Role: Local Counsel
  • Firm: Davis, Cedillo & Mendoza, Inc. (San Antonio, TX)
  • Note: A highly-regarded Texas trial lawyer with over four decades of experience, Cedillo has been recognized for his work in "bet-the-company" cases and intellectual property litigation.

It is common practice in the Eastern District of Texas for out-of-district lead attorneys to associate with an established local firm. While docket information explicitly designating these roles can be limited in early stages, the filing patterns in Greenthread's other cases against defendants like OmniVision and Cirrus Logic show this same lead/local counsel structure. Filings from related PTAB proceedings and other district court cases confirm this legal team is consistently representing Greenthread in its ongoing patent assertion efforts.

Defendant's Counsel of Record

As of May 7, 2026, counsel for Defendant Renesas Electronics America, Inc. has appeared in the case. The company is represented by a team from the intellectual property law firm Fish & Richardson P.C., a firm known for its extensive experience in high-stakes patent litigation, particularly in venues like the Eastern District of Texas.

Based on available docket information, the following attorneys have made appearances on behalf of Renesas:

• David M. Hoffman - Lead Counsel

  • Firm: Fish & Richardson P.C., Minneapolis, MN
  • Note: Hoffman is a seasoned trial lawyer with a focus on patent litigation, having represented major technology companies in complex disputes involving semiconductors, software, and medical devices.

• Gwilym J. O. Attwell - Of Counsel

  • Firm: Fish & Richardson P.C., Washington, D.C.
  • Note: Attwell has experience in various aspects of patent litigation, including proceedings before district courts, the International Trade Commission (ITC), and the Patent Trial and Appeal Board (PTAB).

• Chad E. Ehrenkranz - Of Counsel

  • Firm: Fish & Richardson P.C., Wilmington, DE
  • Note: Ehrenkranz focuses on patent and intellectual property litigation and has been involved in numerous cases for technology and life sciences clients.

• Ricardo J. Bonilla - Local Counsel

  • Firm: Fish & Richardson P.C., Dallas, TX
  • Note: Bonilla serves as local counsel in Texas, leveraging his familiarity with the local patent rules and procedures of the Eastern District of Texas.

• Katie O'Sullivan - In-House Counsel

  • Position: Senior Corporate Counsel, US Litigation at Renesas Electronics America, Inc.
  • Note: O'Sullivan manages and supports U.S.-based litigation for Renesas and previously worked as an IP Litigation Associate at Kirkland & Ellis.

This legal team combines lead trial counsel with specialized patent litigators and essential local counsel, supported by in-house oversight. Their collective experience indicates Renesas is mounting a robust defense, which is typical for a defendant in a broad litigation campaign initiated by a non-practicing entity like Greenthread.

Initial filings in this matter, including the appearances of counsel, were not immediately available through broad web searches. The identification of counsel is based on a detailed review of docket reporting services that aggregate PACER data for this specific case number. Corroborating information on the attorneys' experience was sourced from their respective firm biographies.