PTAB

IPR2025-01385

Volex PLC v. Credo Technology Group Ltd

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Active Electrical Cables with Transmit-Side Equalization
  • Brief Description: The ’233 patent relates to high-speed active electrical cables, such as those used in data centers, which it terms "active Ethernet cables" (AECs). The cables feature pluggable modules at each end containing transceivers that perform signal conditioning, including pre-equalization of signals using transmit filter coefficient values that are stored in non-volatile memory.

3. Grounds for Unpatentability

Ground 1: Obviousness over Lugthart and Gorecki

  • Claims: 1-6, 8-13, and 15-19 are obvious over Lugthart in view of Gorecki.
  • Prior Art Relied Upon: Lugthart (9,882,706) and Gorecki (7,233,617).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Lugthart disclosed all elements of the challenged claims for an active electrical cable except for the specific implementation of storing transmit filter coefficients in non-volatile memory. Lugthart taught an active cable with transceivers at each end that perform pre-equalization (which it calls "pre-emphasis") using multi-tap Finite Impulse Response (FIR) filters. Gorecki, which addresses enhancing high-speed digital communications, explicitly taught storing FIR filter tap coefficients in non-volatile memory (NVM), such as EEPROM, and having a controller retrieve these values to configure the transmitter's equalization circuitry upon start-up or initialization. Petitioner asserted that combining Gorecki’s NVM storage and retrieval method with Lugthart’s active cable system rendered the key limitation of independent claims 1, 8, and 15—storing and using pre-equalization coefficients from non-volatile memory—obvious.
    • Motivation to Combine: Petitioner contended that Lugthart described the use of configurable transmit filters but did not specify how the filter coefficients were to be set or stored, leaving this implementation detail to a person of ordinary skill in the art (POSA). Gorecki was directed to the same technical field of improving high-speed digital communications via equalization. A POSA would combine Gorecki’s well-known method of storing filter coefficients in NVM with Lugthart’s active cable to provide a convenient and reliable way to configure the pre-equalization filters and persist those settings through power cycles. This combination represented a simple application of a known technique to improve a similar device, yielding only predictable results.
    • Expectation of Success: Petitioner argued that a POSA would have had a high expectation of success. The proposed combination involved standard components (active cables, FIR filters, NVM) and conventional techniques for digital pre-equalization that were well-understood and commonly used in high-speed communication systems.

Ground 2: Obviousness over Lugthart, Gorecki, and IEEE 802.3

  • Claims: 7, 14, and 20 are obvious over Lugthart and Gorecki in view of the IEEE 802.3 standard.
  • Prior Art Relied Upon: Lugthart (’706), Gorecki (’617), and IEEE Std. 802.3-2015 ("802.3").
  • Core Argument for this Ground: This ground addresses the remaining claims, which add a negative limitation requiring that the cable's transceivers do not perform pre-equalization on certain multi-lane data streams.
    • Prior Art Mapping: Petitioner argued that the combination of Lugthart and Gorecki taught an active cable capable of performing pre-equalization. The 802.3 standard, which is applicant-admitted prior art for Ethernet communications, explicitly taught how to configure a standard three-tap transmit filter to disable pre-equalization by setting specific tap coefficient values (e.g., setting outer taps to zero and the center tap to its maximum value). By applying this teaching from 802.3 to the configurable filters of the Lugthart/Gorecki combination, a POSA would arrive at a system that meets the negative limitations of claims 7, 14, and 20.
    • Motivation to Combine: The primary motivation for adding the 802.3 teaching was to solve the known problem of excessive power consumption in transceivers. It was well-known in the art that pre-equalization could be disabled if not needed to meet signal quality requirements, thereby reducing power usage. A POSA would have been motivated to implement the disabling functionality taught by 802.3 in the Lugthart/Gorecki cable to create an optional low-power mode, improving the overall system efficiency.
    • Expectation of Success: Petitioner asserted a high expectation of success because disabling pre-equalization via coefficient manipulation was a conventional function for transceivers, explicitly described in a foundational industry standard like 802.3. Implementing this known technique on the configurable FIR filters of the primary references would have been a straightforward task for a POSA.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial is unwarranted. The petition is substantially the same as a previously filed petition (IPR2025-00835), and Petitioner intends to file a motion to join that proceeding. Petitioner contended that a final written decision (FWD) in the co-pending IPR would issue before the trial date in the parallel district court litigation. Further, Petitioner stipulated that it would not pursue in litigation any invalidity ground that was raised or could have been reasonably raised in this inter partes review (IPR) if it is instituted.

5. Relief Requested

  • Petitioner requests institution of IPR and cancellation of claims 1-20 of Patent 10,877,233 as unpatentable.