Eridanus Technologies v. AMD: LDO Regulation Patent Claims Dismissed With Prejudice in 159 Days
Eridanus Technologies, Inc. sued Advanced Micro Devices over on-die LDO voltage regulation patents, targeting AMD’s Ryzen, EPYC, and Threadripper processor lines across more than 15 product families. The case resolved in just 159 days via joint stipulation, with all claims dismissed with prejudice and each side bearing its own legal costs.
Swift with-prejudice dismissal in on-die CPU voltage regulation IP dispute
On September 1, 2023, Eridanus Technologies, Inc. filed suit against Advanced Micro Devices, Inc. in the Western District of Texas (Case No. 1:23-cv-01036) before Judge David Alan Ezra. The complaint alleged infringement of two patents — US7671623B2 and US7372764B2 — both covering on-die low-dropout (LDO) voltage regulation technology. The accused products spanned more than 15 AMD processor families, including EPYC 7001 Series CPUs, Ryzen 1000–3000 Series CPUs and APUs, Ryzen Embedded variants, Ryzen Threadripper 2000 Series, and any future AMD products employing on-die LDO regulation.
The case closed on February 7, 2024, just 159 days after filing, following a Joint Stipulation of Dismissal jointly filed by both parties on February 6, 2024. Judge Ezra granted the stipulation and ordered all claims dismissed in their entirety with prejudice. Critically, the order also specified that each party would bear its own costs, expenses, and legal fees — a mutual arrangement suggesting a negotiated resolution rather than a one-sided capitulation, though the precise terms of any underlying agreement remain confidential.
A 159-day resolution is notably swift for patent litigation in the Western District of Texas, which typically sees cases run well beyond 12 months before trial. The speed of resolution and the with-prejudice, own-costs structure strongly suggest the parties reached a private settlement or licensing arrangement before meaningful claim construction or discovery concluded. What drove early resolution — whether licensing terms, prior art concerns, or commercial considerations — is not disclosed in the public record. The breadth of the accused product list, including a catch-all for ‘any current and future generations of AMD products employing on-die LDO regulation,’ suggests Eridanus had broad enforcement ambitions that were ultimately resolved privately.
Filing to dismissal in 159 days
Case resolved in 159 days — well below the median district court patent case duration
All claims dismissed with prejudice — each party bears its own costs
Joint Stipulation: both sides agreed to end the case
A Joint Stipulation of Dismissal means both plaintiff and defendant actively agreed to terminate the litigation. Unlike a unilateral voluntary dismissal, a joint stipulation requires mutual consent — signalling that neither side was forced out and that some form of agreement, potentially a licensing deal or covenant not to sue, likely underpins the resolution. The court simply ratified the parties’ joint decision.
Mutual resolution mechanismWith prejudice: Eridanus is permanently barred from refiling these claims
A dismissal with prejudice operates as a final adjudication on the merits. Eridanus Technologies cannot refile suit against AMD on the same infringement claims under US7671623B2 or US7372764B2. This is a meaningful legal protection for AMD — it eliminates the risk of Eridanus reasserting these specific patents against the same accused product lines in future litigation, absent a successful appeal, which is unavailable here given the joint nature of the dismissal.
Permanent bar on re-litigationOwn-costs order: no fee-shifting, no admitted liability
The order that each party bear its own costs, expenses, and legal fees is consistent with a negotiated exit. It avoids the signal of one party ‘winning’ on fees and is common in cases that resolve through private agreement. It also means AMD did not pursue — or did not prevail on — a motion for attorneys’ fees under 35 U.S.C. § 285, which would have required a finding of an ‘exceptional case.’ No such finding was made here.
No § 285 fee findingCatch-all clause covered all future AMD LDO products
The complaint’s accused product list included a forward-looking catch-all: ‘any current and future generations of AMD products employing on-die LDO regulation.’ This is an aggressive pleading posture that effectively placed AMD’s entire on-die power management roadmap within the litigation’s scope. A with-prejudice dismissal covering all claims suggests the resolution — whether a licence or covenant — likely addressed this forward-looking exposure as well, not just the named legacy product families.
Forward-looking scope resolvedFull party and counsel information
| Role | Name | Typ | Detail |
|---|---|---|---|
| Kläger | Eridanus Technologies, Inc. | Unternehmen | Patent assertion entity — holder of US7671623B2 and US7372764B2 (on-die LDO regulation)Search in Eureka ↗ |
| Beklagter | Advanced Micro Devices, Inc. | Unternehmen | Advanced Micro Devices, Inc. — global semiconductor company, designer of Ryzen, EPYC, and Threadripper CPUsSearch in Eureka ↗ |
| Plaintiff counsel | David T. DeZern | Attorney | Counsel for Eridanus Technologies, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Edward Nelson , III | Attorney | Counsel for Eridanus Technologies, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Jonathan H. Rastegar | Attorney | Counsel for Eridanus Technologies, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Robert A. Delafield , II | Attorney | Counsel for Eridanus Technologies, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Ryan Griffin | Attorney | Counsel for Eridanus Technologies, Inc.Search in Eureka ↗ |
| Plaintiff counsel | T. William Kennedy , Jr. | Attorney | Counsel for Eridanus Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | Ahimsa E. Hodari | Attorney | Counsel for Advanced Micro Devices, Inc.Search in Eureka ↗ |
| Defendant counsel | Brian K. Erickson | Attorney | Counsel for Advanced Micro Devices, Inc.Search in Eureka ↗ |
| Defendant counsel | Daniel Valencia | Attorney | Counsel for Advanced Micro Devices, Inc.Search in Eureka ↗ |
| Defendant counsel | Jennifer Librach Nall | Attorney | Counsel for Advanced Micro Devices, Inc.Search in Eureka ↗ |
| Presiding judge | Judge David Alan Ezra | Oberster Richter | Texas Western District Court — Chief JudgeSearch in Eureka ↗ |
Stipulation of dismissal — official text
The court’s order adopts the Joint Stipulation verbatim, dismissing all claims with prejudice and imposing no fee award. The ‘with prejudice’ designation is legally significant: it forecloses any future refiling of these specific claims by Eridanus against AMD. The symmetric own-costs ruling signals a negotiated exit rather than a litigated outcome — no party conceded infringement or validity, and no judicial finding on the merits was made. The order’s brevity reflects the court’s limited role in ratifying a privately agreed resolution.
US7671623B2 & US7372764B2 — On-Die LDO Voltage Regulation for Processors
US7671623B2 (application no. US11/701973) and US7372764B2 (application no. US11/200867) both concern on-die low-dropout (LDO) voltage regulation — a technique for managing power delivery directly within a processor die rather than relying solely on external voltage regulators. On-die LDO regulation enables finer-grained, faster-responding power management across processor cores and subsystems, which is critical for performance and energy efficiency in modern CPUs, APUs, and embedded processors. Both patents were asserted as covering the integrated power management architecture deployed across AMD’s Ryzen, EPYC, Threadripper, and Embedded processor lines.
On-die LDO regulation has become a standard design technique in high-performance semiconductor architectures, making these patents strategically significant across the industry. Any processor designer — including Intel, Qualcomm, Arm licensees, and custom silicon teams — implementing integrated voltage regulation may face exposure to similar patent families. The assertion against more than 15 AMD product families, including a forward-looking catch-all clause, suggests Eridanus viewed these patents as broadly applicable across generations of silicon, not merely legacy designs. Companies with on-die power management in their roadmaps should treat this patent family as a monitoring priority.
Should your team run an FTO against US7671623B2 and US7372764B2?
If your organisation designs, manufactures, or licenses processors or SoCs incorporating on-die LDO voltage regulation — including CPUs, APUs, embedded processors, or custom silicon for data centre or edge applications — these two patents warrant direct FTO scrutiny. The Eridanus v. AMD case demonstrates that this technology area is actively asserted, and the broad accused-product list suggests the patents’ claims may be interpreted expansively. R&D teams integrating on-die power management in next-generation designs should not assume that prior AMD case resolution extinguishes risk for other implementers.
PatSnap Eureka’s FTO Search Agent allows you to map the full claim scope of US7671623B2 and US7372764B2 against your specific design architecture in minutes, surfacing relevant prior art and identifying claim elements that may read on your implementation. Eureka’s claim monitoring feature can also alert your team to continuation applications or related family members filed by Eridanus Technologies that may extend coverage beyond the two asserted patents. Proactive FTO analysis before tape-out is substantially less costly than litigation defence after product launch.
Run a freedom-to-operate analysis on US7671623B2 to assess your product’s exposure
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What this case signals for the CPU power management IP landscape
This swift resolution highlights active patent assertion in on-die voltage regulation — a foundational technology across modern processor architectures.
On-die LDO regulation is an active assertion target — monitor it
US7671623B2 and US7372764B2 cover on-die LDO voltage regulation, a technique embedded in virtually all modern high-performance CPUs and APUs. The breadth of accused products — spanning Ryzen, EPYC, and Threadripper — suggests these patents were asserted as broadly applicable. Any company designing or selling processors with integrated power management should assess exposure to these patent families and their continuations.
Western District of Texas remains a favoured venue for NPE patent assertions against chipmakers
Filing in the Western District of Texas (Waco division) is a deliberate strategic choice for patent asserters. The district has historically shown faster scheduling and plaintiff-friendly procedural norms. The 159-day resolution here may reflect AMD’s incentive to settle quickly rather than engage in prolonged litigation in this venue. Semiconductor defendants should weigh venue transfer strategies early when sued in W.D. Tex.
Eridanus v Advanced — key questions answered
Eridanus Technologies asserted two patents: US7671623B2 (application US11/701973) and US7372764B2 (application US11/200867). Both patents cover on-die low-dropout (LDO) voltage regulation technology — a method for integrating power management directly within a processor die. The patents were asserted against more than 15 AMD processor product families including Ryzen, EPYC, and Threadripper lines.
The case was resolved via a Joint Stipulation of Dismissal filed by both parties on February 6, 2024. Judge David Alan Ezra ordered all claims dismissed with prejudice on February 7, 2024. Each party was ordered to bear its own costs, expenses, and legal fees. The case lasted 159 days. The specific terms of any underlying commercial agreement between the parties are not disclosed in the public record.
A dismissal with prejudice means Eridanus Technologies is permanently barred from refiling the same patent infringement claims against AMD under US7671623B2 and US7372764B2. The dismissal operates as a final adjudication on the merits of those specific claims. Eridanus retains ownership of the patents and may assert them against other defendants, but cannot relitigate the same claims against AMD.
The accused products included EPYC 7001 Series CPUs, EPYC Embedded 3000 and 7001 Series CPUs, Pro 3000 Series APUs, Ryzen 1000–3000 Series CPUs and APUs, Ryzen Embedded R1000, R2000, V1000, and 2000 AM4 Series APUs and CPUs, and Ryzen Threadripper 2000 Series CPUs. The complaint also included a catch-all covering any current and future AMD products employing on-die LDO regulation.
The Western District of Texas, particularly the Waco division, has been a preferred venue for non-practising entity (NPE) patent assertions in recent years due to its historically faster scheduling and procedural characteristics. Eridanus Technologies’ choice of this district is consistent with a broader pattern of patent asserters filing against major semiconductor companies in W.D. Tex. to gain procedural advantages, though recent judicial and administrative changes have moderated some of those advantages.
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