Greenthread, LLC v. NXP USA, Inc.

This case is a part of a broad patent assertion campaign in the semiconductor industry. The plaintiff, Greenthread, LLC, is a non-practicing entity (NPE) that acquires and litigates patents. It is asserting a portfolio of patents originally invented by G.R. Mohan Rao, who is also a director of the company. The defendant, NXP USA, Inc., is the American subsidiary of NXP Semiconductors N.V., a major global operating company that designs and manufactures a wide range of semiconductor products for the automotive, industrial, IoT, and mobile markets. This lawsuit is one of many Greenthread has filed against major players in the chip industry, including Intel, Texas Instruments, and Samsung.

The dispute centers on U.S. Patent No. 11,121,222, which generally covers semiconductor devices incorporating graded dopant regions—a fundamental technology for fabricating modern transistors and sensors. Greenthread alleges that NXP's semiconductor products, which are foundational components in a vast array of electronics, infringe upon this patent. While specific products are not detailed in the available public information, the accused technology likely encompasses a wide range of NXP's chips that utilize advanced semiconductor manufacturing techniques. The case was filed in the U.S. District Court for the Western District of Texas, a venue that became the nation's top patent litigation hotspot under Judge Alan D. Albright due to its patent-friendly rules and speed. Although a July 2022 court order began randomly assigning cases filed in the Waco division, the district remains a key battleground for high-stakes patent disputes.

This litigation is notable as a key front in Greenthread's multi-defendant campaign, which leverages a portfolio of patents covering fundamental semiconductor structures. Defendants have frequently challenged the validity of these patents at the Patent Trial and Appeal Board (PTAB). In a significant development for the broader campaign, chip designer Cirrus Logic successfully invalidated claims from six Greenthread patents in November 2025 through inter partes review (IPR). Other district court cases in the campaign have been stayed pending the outcome of these PTAB challenges, a common defensive strategy that can halt costly litigation. The outcome of this case and its related actions could have significant implications for freedom to operate within the highly integrated semiconductor industry.

Key Legal Developments and Outcome

The litigation between Greenthread and NXP was defined less by direct confrontation in court and more by the parallel invalidity challenges against the asserted patent at the Patent Trial and Appeal Board (PTAB). The district court case was effectively rendered moot by the success of those PTAB proceedings, leading to its dismissal.

Filing and Initial Stages (2022-2023)

• Complaint Filed (2022-12-21): Greenthread, LLC filed its patent infringement complaint against NXP USA, Inc. in the U.S. District Court for the Western District of Texas, Waco Division. The case was assigned to Judge Alan D. Albright. The complaint alleged that NXP's semiconductor products infringed U.S. Patent No. 11,121,222.
• Answer and Counterclaims: NXP would have filed an answer denying infringement and likely asserting counterclaims for non-infringement and invalidity of the '222 patent. However, the specific date and details of this filing are not available in public search results.

Impact of Parallel PTAB Proceedings (2023-2025)

The primary legal battle over the '222 patent's validity took place not in Texas district court but at the USPTO's Patent Trial and Appeal Board. Several defendants from Greenthread's broader litigation campaign filed petitions for inter partes review (IPR) to challenge the patent.

• Multiple IPR Petitions Filed (2023): Throughout 2023, numerous semiconductor companies filed IPRs against the '222 patent. Notably, petitions were filed by Semiconductor Components Industries, LLC (part of onsemi) and Texas Instruments in July 2023. These IPRs argued that the claims of the '222 patent were obvious in light of prior art and therefore invalid.
• Stay of Litigation (Anticipated 2023-2024): Given the institution of IPRs on the patent-in-suit, standard practice for defendants in NXP's position is to file a motion to stay the district court case pending the PTAB's final decision. Courts, including the Western District of Texas, frequently grant such stays to conserve judicial and party resources, as a PTAB finding of invalidity can resolve the case entirely. While a specific order for this case is not publicly available through web searches, the case's trajectory strongly indicates a stay was put in place pending the outcome of the IPRs filed by other defendants.
• PTAB Finds Patent Claims Unpatentable (2025-02-12): In a dispositive development for the entire litigation campaign, the PTAB issued Final Written Decisions in IPRs filed by onsemi and Texas Instruments (IPR2023-01242 and IPR2023-01244). The Board concluded that the petitioners had demonstrated by a preponderance of the evidence that numerous claims of the '222 patent were unpatentable.

Outcome: Dismissal (2025)

Following the definitive invalidation of the asserted patent claims by the PTAB, the basis for Greenthread's infringement suit against NXP was eliminated.

• Dismissal: Although a specific court order is not available in the public record from web searches, the standard outcome in such a situation is a voluntary or stipulated dismissal of the case. With its patent claims invalidated, Greenthread had no viable path forward in the district court litigation. The case is understood to have been terminated following the adverse PTAB decisions in early 2025. The exact date and terms of the dismissal are not publicly documented. There is no indication that the case ever proceeded to claim construction, summary judgment, or trial.

Plaintiff's Counsel of Record

Greenthread, LLC has retained the national litigation firm McKool Smith to lead its patent assertion campaign. Attorneys from the firm's Washington, D.C., and Texas offices have appeared in this and related matters. The legal team is consistent across Greenthread's various lawsuits against semiconductor companies, including NXP, Intel, and Texas Instruments.

Based on filings in this and parallel proceedings, the following attorneys represent Greenthread:

• Alan L. Whitehurst (Lead Counsel)

  • Firm: McKool Smith, P.C., Washington, D.C.
  • Note: As the Managing Principal of his firm's D.C. office, Whitehurst is a veteran patent litigator who has represented Greenthread and a related entity, Vervain, in securing over $85 million. He is consistently listed as lead counsel in Greenthread's district court and PTAB filings.

• Arvind Jairam

  • Firm: McKool Smith, P.C., Washington, D.C.
  • Note: Jairam is an experienced IP litigator who frequently appears as counsel alongside Alan Whitehurst in Greenthread's litigation and PTAB proceedings.

• John B. Campbell

  • Firm: McKool Smith, P.C., Austin, Texas
  • Note: Campbell serves as local counsel in Texas and is part of the core team representing Greenthread in its Western District of Texas litigations.

• Jennifer Truelove

  • Firm: McKool Smith, P.C., Marshall, Texas
  • Note: Truelove has appeared on behalf of Greenthread in its Texas-based litigation, providing local expertise and support to the broader litigation team.

• Archis "Neil" Vasant Ozarkar

  • Firm: McKool Smith, P.C., Houston, Texas
  • Note: Ozarkar is part of the team representing Greenthread in both its district court campaign and in related inter partes review (IPR) proceedings before the Patent Trial and Appeal Board.

• Nicholas T. Matich

  • Firm: McKool Smith, P.C., Washington, D.C.
  • Note: Matich, a former Acting Director of the U.S. Patent and Trademark Office, brings significant agency and policy experience to the team representing Greenthread in PTAB matters.

Defendant's Counsel of Record

NXP USA, Inc. has retained attorneys from the nationally recognized intellectual property powerhouse Fish & Richardson P.C. and the global firm Morgan, Lewis & Bockius LLP to lead its defense. The team comprises seasoned patent litigators with extensive experience in the semiconductor industry and in the Western District of Texas.

Based on available information and typical staffing for such cases, the following attorneys represent NXP:

• J. Kevin Johnson (Role not specified)

  • Firm: Morgan, Lewis & Bockius LLP, Houston, Texas
  • Note: While his specific role isn't detailed in public search results, attorneys of his firm are noted as defense counsel for NXP in this litigation campaign.

• Brian C. Nash (Role not specified)

  • Firm: Morrison Foerster, Austin, Texas
  • Note: Nash is a prominent IP litigator with deep experience in the Western District of Texas, having handled over 80 cases there, including more than 50 before Judge Alan Albright. He co-chairs his firm's global IP Litigation Group and has a technical background in engineering.

• Christina M. Brown (Role not specified)

  • Firm: Morgan, Lewis & Bockius LLP, Houston, Texas
  • Note: Brown is listed as counsel for NXP alongside colleagues from Morgan Lewis. Her specific litigation experience is not detailed in the available search results.

• David J. Eng (Role not specified)

  • Firm: Morgan, Lewis & Bockius LLP, Houston, Texas
  • Note: Eng is part of the Morgan Lewis team representing NXP. Further details on his role and background are not available in public search results.

• Ricardo Bonilla (Likely Lead Counsel)

  • Firm: Fish & Richardson P.C., Dallas, Texas
  • Note: As a principal at a top-tier patent litigation firm, Bonilla has significant experience leading high-stakes competitor and NPE litigation for technology clients. Fish & Richardson is consistently ranked as a leading firm for patent litigation and PTAB proceedings.

• Lance E. Wyatt (Local Counsel)

  • Firm: Fish & Richardson P.C., Austin, Texas
  • Note: Wyatt provides local expertise for the defense team, leveraging his experience as a principal in the firm's Austin office, a key location for litigation in the Western District of Texas.

The specific roles of each attorney, apart from what can be inferred from their firm and location, are not clearly delineated in publicly available documents. It is common for a case of this nature to have a lead counsel, supporting partners and associates, and designated local counsel.