Western Digital vs. Longitude Licensing: Dismissed Appeal in Supply Voltage Circuit Patent Case

In a case that concluded without a merits ruling, Western Digital Corp. and Longitude Licensing, Ltd. jointly moved to dismiss their Federal Circuit appeal just over 300 days after it was filed. Case No. 25-1584, centered on U.S. Patent No. 9,207,701B2 covering supply voltage generating circuit technology, was voluntarily dismissed under Federal Rule of Appellate Procedure 42(b), with each party bearing its own costs.

While the dismissal leaves no binding precedent on the underlying infringement claims, the case offers meaningful intelligence for patent attorneys, IP professionals, and R&D teams operating in the semiconductor and power management technology space. The involvement of Haynes & Boone, LLP representing Western Digital and Russ August & Kabat LLP representing Longitude Licensing signals the seriousness with which both sides initially approached the dispute—making the negotiated exit all the more strategically significant.

For practitioners tracking supply voltage patent litigation and Federal Circuit appellate trends, this case is a notable data point in the broader pattern of voluntary resolution at the appellate stage.

Case Overview

The Parties

The Patent at Issue

The disputed patent, U.S. Patent No. 9,207,701B2 (Application No. US14/480768), covers a supply voltage generating circuit—a fundamental component in semiconductor device architecture that regulates internal voltage levels essential to stable memory and processor operation. Such circuits are critical to NAND flash and DRAM memory products, areas squarely within Western Digital’s commercial operations.

The Accused Product

The accused technology—supply voltage generating circuits—appears in the power management infrastructure of semiconductor storage devices. Given Western Digital’s product portfolio, the implied target was likely circuit implementations embedded within flash storage or memory controller architectures, though specific product models were not disclosed in the available case record.

Legal Representation

Plaintiff (Western Digital): Haynes & Boone, LLP — Attorneys Angela M. Oliver, David M. O’Dell, Debra Janece McComas, Hong Shi, and Laura Vu

Defendant (Longitude Licensing): Russ August & Kabat LLP — Attorneys Brian David Ledahl and Paul Anthony Kroeger

The Verdict & Legal Analysis

Litigation Timeline & Procedural History

The case was filed at the Court of Appeals for the Federal Circuit—the exclusive appellate venue for U.S. patent disputes—on March 25, 2025. Its classification as an appeal indicates that underlying proceedings at the district court level preceded this filing, though the specific district court record and prior rulings are not included in the available case data.

The 302-day duration from filing to dismissal is notably shorter than the Federal Circuit’s median disposition time for fully briefed patent appeals, which typically ranges from 12 to 18 months. This compressed timeline strongly suggests that settlement or licensing negotiations were already advanced at the time of filing, or accelerated significantly during the appellate briefing schedule.

The case was terminated under Fed. R. App. P. 42(b), the standard mechanism for voluntary dismissal of an appeal by stipulation of the parties. No damages amount, injunctive relief, or merits ruling was issued. Specific information regarding the chief judge assigned to the panel was not disclosed in the available case record.

Outcome

The Federal Circuit dismissed Case No. 25-1584 pursuant to a joint stipulation under Fed. R. App. P. 42(b). The dismissal order specified that each side shall bear its own costs—a standard provision in mutually agreed appellate dismissals that neither confirms nor implies fault or liability by either party.

No damages were awarded, no injunction was entered, and no claim construction or validity determination was issued on the merits of U.S. Patent No. 9,207,701B2. The underlying infringement action therefore remains unresolved as a matter of public legal record.

Verdict Cause Analysis

The case was docketed as an infringement action, meaning Western Digital—as appellant—was challenging a lower tribunal’s ruling related to alleged infringement of the supply voltage generating circuit patent asserted by Longitude Licensing. The specific claim construction disputes, invalidity arguments, or infringement findings from the district court level are not available in the provided record.

What the record does confirm is that both parties affirmatively agreed to end the appeal, suggesting that the litigation risk calculus shifted sufficiently for both sides to prefer resolution outside a Federal Circuit ruling. For Longitude, a licensing-focused entity, a negotiated outcome with Western Digital—one of the world’s largest storage manufacturers—would represent a commercially rational exit. For Western Digital, avoiding an adverse Federal Circuit ruling on supply voltage circuit claims that could affect broader product lines is a credible strategic motivation.

Legal Significance

Because the Federal Circuit dismissed the case without issuing a merits opinion, no binding precedent was established regarding the validity or infringement scope of U.S. Patent No. 9,207,701B2. Patent attorneys should note that the patent’s claims remain intact as issued, and no estoppel or disclaimer was created by this proceeding’s outcome alone.

The case does not resolve questions around claim construction of “supply voltage generating circuit” limitations, nor does it address potential invalidity challenges that may have been raised at the trial level.

Industry & Competitive Implications

The Western Digital v. Longitude Licensing dismissal reflects a well-established pattern in semiconductor patent litigation: patent assertion entities leverage appellate proceedings as settlement catalysts rather than purely as vehicles for merits adjudication.

For the broader data storage and semiconductor industry, this case highlights ongoing exposure to supply voltage and power management patent claims. As NAND flash and next-generation storage architectures grow increasingly sophisticated, circuit-level patent portfolios held by licensing entities will continue to generate assertion activity against manufacturers.

Companies in Western Digital’s competitive space—including SK Hynix, Micron Technology, Samsung Semiconductor, and Kioxia—should monitor Longitude Licensing’s assertion activity and patent portfolio for overlapping supply voltage claims. The resolution of this appeal without a merits ruling means that Longitude retains full enforcement rights on U.S. Patent No. 9,207,701B2 against other potential defendants.

From a market perspective, the “each party bears its own costs” provision suggests a clean separation with no publicly disclosed licensing payment, though confidential settlement terms cannot be ruled out. IP professionals should treat this outcome as consistent with a confidential licensing resolution rather than a clear plaintiff or defendant victory.