US 11402440

I'll search for authoritative information on US 11,402,440, including any 2026 CAFC docket activity.

Let me check for any litigation or CAFC docket activity specific to this patent.

US 11,402,440 B2 — Verified Summary

Caveat on scope of search: I searched for the literal number 11402440 / "11,402,440" and for CAFC 2026 docket activity. The patent data below comes from the USPTO/Google Patents full text (authoritative). I found no CAFC 2026 appeal docket, no PTAB proceeding, and no district court case naming this patent. That is a negative search result, not proof of absence — my searches were not an exhaustive PACER/Docket Alarm sweep, so treat "no litigation found" as low-confidence.

Bibliographic data

Abstract (as issued)

A method and apparatus for trimming a magnetic field sensor having a first magnetic field sensing element. Trimming uses a curve for normalized sensitivity derived from (i) a first curve corresponding to current through a coil in a first direction at a first time producing a field affecting the sensing element versus an external field, and (ii) a second curve corresponding to current through the coil in the opposite direction at a second time producing a field affecting the sensing element versus an external field.

Prosecution posture (from the legal-events record)

Final rejection mailed 2019-03-19 → notice of appeal 2021-04-22 → appeal brief 2021-09-22 → further non-final actions → notice of allowance 2022-05-19. The issued claims are materially narrower than the published application: the published/EP version claimed 34 claims directed to one-element and two-element (differential) sensors, while the granted US patent has 22 claims re-directed to a four-element/six-lead-type configuration. This is consistent with the claim-narrowing history.

Plain-language overview of the independent claims

Claim 1 — Method (the only independent method claim)

The apparatus being trimmed — everything sits inside a single IC package:

• Four magnetic field sensing elements (the specification's favored example: Hall plates, e.g., quad Hall);
• Four coils, one per sensing element, wired by at least one conductive path so that current flows through every coil in the same direction;
• An amplifier coupled to the sensing elements;
• A back-bias magnet.
• Structural limitation: each coil has more than one turn and is wound in a single direction (no counter-wound turns within a coil).

The trimming steps:

1. Apply a first current in a first direction through each coil → produces fields at the sensing elements.
2. Measure the sensor output over time → generate a first curve.
3. Apply a second current in the opposite direction through each coil.
4. Measure the sensor output over time → generate a second curve.
5. Combine the two curves to determine normalized sensitivity data that is "consistent over changes in an external field" applied to the elements due at least in part to the back-bias magnet inside the package.
6. Store that normalized sensitivity data in memory.
7. Adjust the absolute gain of the amplifier according to the stored data.

The inventive point: the specification explains (FIGS. 8–9, 11) that coil sensitivity S_coil is not independent of the external field — a false apparent sensitivity shift that corrupts both absolute-gain trim and temperature-coefficient trim. Driving current in both polarities and combining the resulting curves (e.g., averaging NCS1 and NCS2 into curve CSA) yields a field-independent coil sensitivity, enabling ~1% or better absolute trim accuracy.

Claim 15 — Device (the only independent device claim)

The apparatus counterpart with the same hardware package (four sensing elements, four coils in the same-current-direction topology, amplifier, back-bias magnet, each coil multi-turn and single-direction wound), plus:

• a coil driver circuit configured to apply the first current in the first direction during a first time period and the second (reverse) current during a second time period;
• a memory; and
• a signal processor configured to measure output over each time period, generate the first and second curves, combine them into field-consistent normalized sensitivity data, store it, and adjust the absolute gain of the amplifier.

Dependent claims (briefly)

• 2: external field first polarity is negative. 3: normalized sensitivity = average of the two curves. 4: coils integrated with the sensing elements. 5: sensitivity in LSB/mA. 6: sensitivity in LSB/Gauss. 7: coils integrated in the same silicon as the sensing elements. 8: sensing elements are Hall elements. 9: coil sensitivity determined with no external field, prior to packaging. 10: gain adjustment performed during production test. 11: the amplifier is a front-end analog amplifier. 12: memory is a PROM. 13: the four coils are connected in series by the conductive path. 14: first pair in series, second pair in series, the two pairs in parallel. 16–22 mirror 3, 4, 5, 8, 9, 13, 14 for the device claim.

Analyst notes / points of interest

1. Specification vs. claims mismatch. The issued independent claims recite four sensing elements, four coils, a back-bias magnet, and single-direction-wound multi-turn coils. The specification's Summary and the ABSTRACT instead describe one-element and two-element (differential, "left/right") embodiments with left/right coil polarity reversal and rare-earth pellet back-bias. The four-element/same-direction-coil limitations appear to be a prosecution-driven narrowing to a quad-Hall configuration (cf. FIGS. 14A/14B, which show split vs. serial current through quad Hall elements).
2. Claim 1 requires same-direction current through all four coils, whereas the specification's averaging technique (FIGS. 13E/F) describes left and right coils carrying opposite currents simultaneously ("polarity 1 left combined with polarity 2 right"). Those are different physical configurations; the claim language is controlling.
3. The "combining" step is functional. Claim 1 does not specify averaging numerically, though dependent claim 3 does; the specification also discloses rotating one curve about the y-axis (FIG. 11A) as an alternative to averaging.
4. Family note: EP 3325989 B1 claims (as published) recite the broader one- and two-element subject matter, indicating the US claims were narrowed relative to the PCT/EP family.
5. Any ongoing 2026 CAFC activity involving this patent could not be confirmed. If you need a definitive docket check, PACER (appellate CM/ECF) and the CAFC daily docket for the specific patent number, plus Docket Alarm / CourtListener for the patent number, would be the authoritative sources — my web searches returned no hit.

I'll search for litigation involving US patent 11402440 across the specified sources.

Let me search more targeted litigation databases.

Litigation Search Results for U.S. Patent No. 11,402,440

No litigation is known involving U.S. Patent No. 11,402,440.

I searched for litigation specifically naming this patent (not similar numbers) across the sources you identified — the Unified Patents litigation portal, Docket Alarm, the CAFC opinions/orders database, and general web searches keyed to the exact number "11402440" and the "11,402,440" format. None of these searches surfaced any district court complaint, CAFC appeal, or PTAB proceeding (IPR/PGR) that names U.S. Patent No. 11,402,440 as an asserted or challenged patent.

Summary table

What the searches did return (and why they are not responsive)

• The exact string "11402440" surfaced unrelated items, e.g., a UK Gazette company-incorporation entry ("11402440 07/06/2018") and a Texas bankruptcy docket line ending in a different number. Neither concerns this patent.
• Broader searches (e.g., "Allegro Microsystems patent 11402440 lawsuit") returned only the patent's own bibliographic/ prosecution pages (e.g., uspto.report), not any case asserting it.
• Other hits involved different patents and parties (Unified Patents PTAB matters, Boston Scientific v. Nevro IPR2022-00511, Pfizer/Merck/Wyeth vaccine-patent litigation) that merely happened to contain the digit sequences or were returned as noise. I have deliberately excluded these because they do not name U.S. 11,402,440.

Context on the patent (for completeness, not litigation)

• Patent: U.S. 11,402,440 B2, "Methods and apparatus for trimming a magnetic field sensor"
• Assignee: Allegro Microsystems, LLC
• Application: 14/801,997; filed 2015-07-17; granted 2022-08-02; adjusted expiration 2036-02-19
• Family/related publications: US20170016965A1, WO2017014970A1, EP3325989B1 (EP application 16744988.3)
• Litigation-relevant note: The Google Patents "Cited By" and "Families Citing" tables list only later patents citing this family (e.g., other Allegro, Melexis, and Texas Instruments patents) — these are citations, not litigation. The only litigation-adjacent activity appearing in the record is the PCT/EP prosecution history (e.g., a European Examination Report dated Sep. 1, 2021 and responses), which is prosecution, not litigation.

Important caveats

1. No affirmative evidence of litigation ≠ confirmed absence. My searches relied on public, largely free databases and general web indexing. If any case exists, it would likely be very recent, sealed, or filed in a venue/index I could not fully query. The Unified Patents portal and PACER/Docket Alarm searches I could reach did not return a hit, but I could not guarantee real-time completeness across every docket (e.g., all PACER districts and all CAFC dockets).
2. Allegro Microsystems is an active patent enforcer generally, so future or unindexed assertions are possible — but I found nothing tying any such assertion to this specific patent number.
3. Recommendation: For a definitive negative, confirm via a paid/comprehensive docket service (LexisNexis, Westlaw Litigation Analytics, Docket Navigator, or RPX/Unified litigation search) filtered on the exact patent number 11,402,440, and check PACER directly. I am flagging this rather than asserting certainty.

If you'd like, I can run additional targeted queries (e.g., against specific districts where Allegro has litigated, or the CAFC docket for appeals mentioning Allegro) to try to close the gap.

I'll verify the empty canonical list with targeted searches before writing up.

PTAB / AIA Trial Analysis — U.S. Patent No. 11,402,440 B2

Source of record: USPTO Open Data Portal (ODP) structured "PTAB proceedings on file" block supplied with this task. Canonical result: no AIA trial proceedings on file. I verified this with targeted web searches (below) and found nothing contradicting it. Every substantive field in the template below is therefore marked as not applicable rather than populated with speculation.

Proceedings overview

Total AIA trial proceedings: 0. Breakdown: 0 active, 0 with claims invalidated, 0 with claims sustained, 0 settled, 0 with institution denied, 0 pending institution decisions. The correct defensive framing is not "the patent has survived two IPRs and is hardened" and not "claims are canceled" — it is that U.S. 11,402,440 has never been challenged at the PTAB, so all 22 claims stand exactly as granted on 2022-08-02, and there is no estoppel, no FWD, and no PTAB record to lean on. A defendant facing assertion today must build its invalidity case from scratch; it also retains the full § 315(b) one-year window and an unlimited-art-field IPR (subject to § 311's patents-and-printed-publications limit) if it is served with a complaint.

Corroborating searches (negative results)

No proceeding entries are reproduced below because none exist. I will not invent proceeding numbers, panels, or dispositions.

Proceedings detail

Not applicable — zero proceedings identified. For completeness, the template that would be populated for each proceeding (numbered IPR20XX-##### / PGR20XX-##### / CBM20XX-#####) is empty for every field: type, filing date, status, panel, grounds, institution decision, FWD, settlement, appeal, defensive value.

Strategic summary

Claim status at the PTAB: all claims UNTESTED. No claim of U.S. 11,402,440 has ever been canceled, confirmed, or construed by the Board. The granted claim set is the 22 claims issued 2022-08-02: independent claim 1 (method) and independent claim 15 (device), with dependents 2–14 and 16–22. The claim set was already narrowed during ex parte prosecution — the granted claims recite a four-sensing-element / four-coil architecture with all coils carrying current in the same direction, a multi-turn single-direction coil winding, an amplifier, and a back-bias magnet inside the IC package, whereas the published US 2017/0016965 A1 and EP 3325989 B1 family members claim the broader one- and two-element (differential) subject matter. That narrowing matters defensively: an assertion under this patent will be directed at a quad-sensing-element, back-biased part, and the "same-direction current through all four coils" limitation is a concrete, testable structural element that was added for allowance (see my earlier analyst note flagging that FIGS. 13E/13F teach opposite left/right coil currents — a specification-vs-claim tension worth preserving for a § 112 or claim-construction fight).

Estoppel landscape: a blank slate — and that cuts both ways. Because no petitioner has taken an FWD, there is no § 315(e)(2) estoppel binding anyone. A defendant is free to raise any § 102/§ 103 ground in an IPR and any ground (including § 101 and § 112) in district court. Equally, the patent owner is free of any adverse PTAB record it would otherwise have to live down — the file history, with its 2019 final rejection, 2021 notice of appeal, appeal brief, and 2022 notice of allowance, is the only invalidity-procedure story the patent carries. Note the appeal-brief/allowance sequence: the applicant fought and won allowance after a final rejection, and the winners' brief may contain admissions about the scope of the pre-narrowing claims that could be mined under prosecution history estoppel or as § 112 support arguments.

Pattern signals. No repeat petitioner, no Unified Patents or other defensive-aggregator involvement, no patent-owner PTAB appeal practice on this patent, no CAFC appeal from any FWD. Allegro MicroSystems is an active and sophisticated patent owner that has litigated and IPR'd elsewhere (its name appears across the reexamination/opposition record and in the "Cited By" family citations for this patent), but nothing in the record ties that activity to this patent number. The absence of any IPR is consistent with the patent's profile: a production-test/trimming method-and-apparatus claim tied to a specific quad-Hall back-biased hardware topology is a difficult target for a generic prior-art IPR, and Allegro's commercial parts (the ATS/ATS16xx-class differential gear-tooth sensors) are the natural assertion vehicles.

Recommended next steps

If you are a defendant facing (or anticipating) assertion of U.S. 11,402,440:

1. Do not expect a PTAB roadmap. There is no FWD to cite, no canceled claim to point to, and no institution decision to borrow. Your invalidity case must bebuilt independently. Start from the 28 U.S. references in the patent's own "Citations" table (listed on the Google Patents page and in the printed patent's front page), which is the examiner's and applicant's own prior-art universe and is a defensible jumping-off point for § 102/§ 103.
2. Attack the narrowing limitation and the specification mismatch. Claim 1 requires same-direction current through all four coils and single-direction-wound multi-turn coils. The specification's own averaging embodiment (FIGS. 13E/13F, "polarity 1 left combined with polarity 2 right") describes opposite currents in adjacent coils. If a defendant's accused product does not implement the claimed same-direction topology, or if the claim is sought to be read onto a two-element differential part, the gap between the specification and the issued claims is the pressure point. Consider whether § 112 written-description support exists for the four-coil/same-direction recitation, given its apparent prosecution origin.
3. Watch the § 315(b) clock. If a complaint is served, the one-year IPR bar runs from service. Because claim 1 is a method claim and the device claim 15 is apparatus-plus-functional-language ("configured to"), a § 101 eligibility challenge is also available in district court but not in an IPR (IPR is limited to § 102/§ 103 on patents and printed publications under § 311(b)).
4. Check the family for collateral estoppel leverage. EP 3325989 B1 (granted 2024-02-28 from EP 16744988.3) claims the broader subject matter and has its own EPO prosecution record, including a European Examination Report dated 2021-09-01 and responses filed 2022-03-11. The EPO files are not estoppel, but they are useful evidence of what the applicants and the family considered patentable, and they may reveal prior art not cited in the US file.
5. The absence of PTAB activity is a signal, not a shield. Well-asserted patents eventually attract IPRs; this one has not, which suggests either low assertion volume to date or a claim set that is unattractive to challenge on printed-publication art alone. Either way, you do not get the benefit of someone else's invalidity work product.

On live-tracking the PTAB situation

• USPTO PTAB End-to-End (E2E) / PTAB Center: https://ptacts.uspto.gov/ptacts/ and the PTAB Decision search at https://www.uspto.gov/patents/ptab — search by patent number 11,402,440.
• Docket Alarm PTAB docket: https://www.docketalarm.com/cases/PTAB/ — filter by patent number.
• Unified Patents litigation/PTAB portal: https://portal.unifiedpatents.com/ptab/caselist — filter by patent 11402440 and by owner "Allegro MicroSystems."
• Federal Circuit / CourtListener for any appeal from a future FWD: https://www.courtlistener.com/ and https://cafc.uscourts.gov.

Caveat on confidence

The negative result is a negative search result, not proof of absence. The ODP structured block is the authoritative canonical list and it is empty, and my independent searches returned no contradicting proceeding. But ODP ingest lags, and a very recently filed petition — or one indexed only in a paywalled docket service (DOCKET NAVIGATOR, RPX, LexisNexis Litigation Analytics) — could fall outside what I could reach. Recommendation: re-run the E2E patent-number search immediately before relying on this analysis for a filing or a case strategy decision. If a petition has since been filed, the institution-decision deadline is six months from the petition's filing date, and the FWD is due within 12 months of institution (35 U.S.C. § 316(a)(11)).

I'll verify the assignment records against public sources before reconstructing the chain.

Let me pull the recorded-assignment details and correspondent data from assignment-record aggregators.

Ownership & Assignment Reconstruction — US 11,402,440 B2

Verification links: USPTO Assignment Center (query by patent number 11402440) · Google Patents legal events · USPTO PatentCenter

Evidence-grade caveat up front. The reel/frame numbers and conveyance types below come verbatim from the Google Patents legal-events record reproduced in the authoritative patent text for this matter. I could not retrieve the "correspondent of record" field for any of these recordings from the free/indexed sources reachable in this session — Google Patents legal events do not carry correspondent data, and my searches for aggregator copies of the Assignment Center abstracts returned nothing for this patent. I therefore report correspondent as not retrieved rather than guessing. This is a material gap for the signal-#3 analysis below.

Inventors

Pattern assessment — no departure signal. All three assignors executed the assignment to Allegro the day before filing (execution date 2015-07-16; filing/recording 2015-07-17), i.e., a conventional at-filing employment assignment. There is no evidence of inventors departing the original assignee within 12 months of filing; to the contrary, the record shows at least one inventor (Lapomardo) continuing to be credited on Allegro filings years later. This is not a fire-sale precursor pattern.

Original assignee

ALLEGRO MICROSYSTEMS, LLC — named as applicant/assignee at filing with a Worcester, MA address, and confirmed on the EP register (EP 3325989 B1) at 955 Perimeter Road, Manchester, NH 03103-3353.

• Primary line of business: design, fabrication, and sale of magnetic sensor ICs and power ICs — Hall-effect and TMR/GMR/AMR position, speed, and current sensors, largely for automotive and industrial markets. The patent's claimed subject matter (four Hall elements, four integrated trim coils, a back-bias magnet, all in one IC package) maps directly onto Allegro's back-biased gear-tooth/differential speed-sensor product families (the ATS/ATS16xxx-style two-wire and three-wire speed sensors that use an integrated rare-earth pellet). This is a shipped-product portfolio, not a paper patent.
• Corporate status: operating. Allegro MicroSystems, LLC is the wholly owned operating subsidiary of Allegro MicroSystems, Inc. (Nasdaq: ALGM, a Delaware corporation), which completed its IPO in late October 2020. Sanken Electric Co., Ltd. is the majority/controlling stockholder. Allegro is an active, revenue-generating semiconductor supplier; it is not dissolved, in bankruptcy, or an IP-holding shell. Its 10-K disclosures confirm substantial secured debt financing, which is what drives the security-interest recordings below.
• No change-of-name or internal-reorg assignment was recorded against this patent. The patent never moved from the LLC to the public parent (Allegro MicroSystems, Inc.) on the record, even though AML is the wholly owned subsidiary through which the group holds its operating assets.

Assignment timeline

Six recorded events. Only the first conveys ownership; the other five are collateral/security and release recordings that convey no title.

1. Original employment assignment

• 2015-07-16 (executed) / recorded 2015-07-17 — Reel 036124/0202
  • Conveyance: Assignment (Assignment of Interest)
  • Assignors: Chaware, Virag V.; Lapomardo, Jesse; Haas, David J. (individually)
  • Assignee: ALLEGRO MICROSYSTEMS, LLC (Massachusetts)
  • Correspondent: not retrieved — the public record I could reach omits this field; Assignment Center will show it.
  • Context: Original at-filing employment assignment; the inventors assigned their rights to their employer one day before the application was filed, and the recording was made on the filing date.

2. 2020 secured-financing collateral package (two pari-passu recordings, same day)

• 2020-09-30 (executed) / recorded 2020-10-01 — Reel 053957/0620
  • Conveyance: Patent Security Agreement (security interest only — no title transfer)
  • Assignor: ALLEGRO MICROSYSTEMS, LLC
  • Assignee: MIZUHO BANK, LTD., as Collateral Agent (New York)
  • Correspondent: not retrieved.
  • Context: Securitization — collateral for the $50.0 M Revolving Credit Facility dated September 30, 2020 (Mizuho as administrative agent and collateral agent), taken together with the Credit Suisse term-loan lien below.
• 2020-09-30 (executed) / recorded 2020-10-01 — Reel 053957/0874
  • Conveyance: Patent Security Agreement (security interest only)
  • Assignor: ALLEGRO MICROSYSTEMS, LLC
  • Assignee: CREDIT SUISSE AG, CAYMAN ISLANDS BRANCH, as Collateral Agent (New York)
  • Correspondent: not retrieved.
  • Context: Securitization — collateral for the $325.0 M Senior Secured Term Loan Facility dated September 30, 2020 (Credit Suisse as administrative and collateral agent); per the 10-K, borrowings are secured by substantially all assets including IP.

3. 2023 refinancing — old liens released, new lien recorded

• recorded 2023-06-22 — Reel/Frame not exposed in the record I reached (conveyance text references the discharged lien at R/F 053957/0620)
  • Conveyance: Release of Security Interest in Patents (R/F 053957/0620) — not a title transfer; a lien discharge
  • Assignor: MIZUHO BANK, LTD., as Collateral Agent
  • Assignee: ALLEGRO MICROSYSTEMS, LLC (lien released back to the grantor)
  • Correspondent: not retrieved.
  • Context: Internal refinancing/release — the 2020 revolving-facility lien was discharged in connection with the June 21, 2023 Revolving Credit Agreement with Morgan Stanley Senior Funding, Inc.
• recorded 2023-06-22 — Reel/Frame not exposed in the record I reached
  • Conveyance: Patent Security Agreement (security interest only)
  • Assignor: ALLEGRO MICROSYSTEMS, LLC
  • Assignee: MORGAN STANLEY SENIOR FUNDING, INC., as the Collateral Agent
  • Correspondent: not retrieved.
  • Context: Securitization — new collateral package for the 2023 revolver/term-loan structure (Morgan Stanley Senior Funding as administrative agent, collateral agent and lender), executed alongside the $250 M 2023 Term Loan Facility dated October 31, 2023.
• recorded 2023-11-01 — Reel/Frame not exposed in the record I reached (conveyance text references Reel 053957/Frame 0874)
  • Conveyance: Release of Security Interest in Patents at Reel 053957/Frame 0874 — lien discharge
  • Assignor: CREDIT SUISSE AG, CAYMAN ISLANDS BRANCH, as Collateral Agent
  • Assignee: ALLEGRO MICROSYSTEMS, LLC (lien released back to the grantor)
  • Correspondent: not retrieved.
  • Context: Refinancing release — proceeds of the new Morgan Stanley-agented 2023 Term Loan Facility repaid the 2020 Credit Suisse term loan, and the Credit Suisse IP lien was released the following day.

Net ownership position after all six events: the patent is held unencumbered-in-title by ALLEGRO MICROSYSTEMS, LLC, subject to a current security interest in favor of Morgan Stanley Senior Funding, Inc., as Collateral Agent. There has never been an ownership transfer away from the original assignee.

Timeline diagram

timeline
    title Ownership of US 11402440
    2015 : Filed by Allegro MicroSystems LLC
         : Inventors assign rights to Allegro
    2020 : Mizuho lien on patent recorded
         : Credit Suisse lien on patent recorded
    2023 : Mizuho lien released
         : Morgan Stanley lien recorded
         : Credit Suisse lien released

NPE / troll-pattern signals

Verdict

Insufficient data — and this label is chosen only because the taxonomy has no "clean operating-company chain, no assertion" bucket.

Substantively, the ownership record is the opposite of an NPE pattern: the one title-conveying event is the original employment assignment at Reel 036124/0202 (executed 2015-07-16, recorded 2015-07-17), and the patent has remained with Allegro MicroSystems, LLC — an operating IC manufacturer shipping back-biased Hall-effect sensor products that embody the claims — ever since. All five later recordings (Reel 053957/0620 and 053957/0874 recorded 2020-10-01; the Mizuho release and Morgan Stanley security agreement recorded 2023-06-22; the Credit Suisse release recorded 2023-11-01) are lender collateral and lien-discharge filings that transfer no title, tracking Allegro's 2020 and 2023 credit facilities; because no post-issuance ownership transfer exists, there is no chain to test against the NPE signals, which is why the verdict lands on "Insufficient data" rather than a "Defensive / non-asserting" call.

Two gaps the reader should close before relying on this: (i) correspondent-of-record was not retrievable for any of the six recordings — pull each abstract on Assignment Center by patent number 11402440 to capture the reel/frame and correspondent for the 2023 events, which my source text listed without reel/frame; and (ii) the prior Litigation section's "no suit found" result is a negative search, not proof of absence, so the pre-litigation-transfer signal (#5) cannot be treated as definitively closed.

I'll search the USPTO database for patent 11402440 and then examine each cited prior-art reference.

Let me examine the front-page "References Cited" section and key references in detail.

Prior-Art Analysis — U.S. Patent No. 11,402,440 B2

Method note / confidence: I worked from the authoritative full text of US 11,402,440 (Google Patents / USPTO record, fetched 2026-09-24), which includes the patent's own "Citations" and "Patent Citations" lists, plus targeted searches on the individual references. I did not retrieve the literal facsimile front-page "(56) References Cited" block from the granted PDF, so the citation inventory below is taken from the patent record's citation lists (which normally mirror the front page). Where a date or characterization is uncertain I say so. No identifier has been auto-corrected — every number is reproduced literally as it appears.

1. Confirmation of the target document (USPTO record)

This is the same document analyzed in the earlier sections (summary and litigation). The earlier observation that the granted independent claims were narrowed to a four-sensing-element / four-coil, same-current-direction, back-bias-magnet topology while the specification/abstract describe one- and two-element embodiments is confirmed by the claim text and is central to the § 102 analysis below.

2. Complete list of references cited in US 11,402,440

Legend: Dates are shown as (earliest priority/filing date → publication or grant date) exactly as listed in the patent record. "Ex." = marked as cited by the examiner in the record.

A. Patent citations (28 documents)

(The record's "Patent Citations (34)" list is the same set expanded by family members — e.g., US 8,447,556 B2 ↔ US 2010/0211347 A1; US 8,542,010 B2 ↔ US 2011/0018533 A1 and US 2013/0335066 A1; US 8,680,846 B2 ↔ US 2012/0274314 A1; US 2013/03335068A1 etc. No new technical content.)

B. Non-patent citations (9)

1. European Examination Report dated 2021-09-01, EP Application No. 16744988.3 (5 pp.).
2. Ian Sinclair, Abstract of Chapter 13 — Microprocessors, Calculators, and Computers, Newnes, Electronics Simplified (3rd ed.), 2011 (cited by examiner).
3. Overview of Microprocessors, Chapter 1 (Smith College course reading) (cited by examiner).
4. PCT International Preliminary Report dated 2018-02-01, PCT/US2016/041697 (14 pp.).
5. PCT Search Report and Written Opinion of the ISA for PCT/US2016/041697, dated 2016-10-12 (18 pp.).
6. Response to European Examination Report dated 2021-09-01, filed 2022-03-11 (26 pp.).
7. Response to Examination Report dated 2021-09-01, filed 2022-03-11 (EP 16744988; 26 pp.).
8. Response to Official Communication of 2018-02-23, filed 2018-08-22 (17 pp.).
9. U.S. Appl. No. 14/255,166, filed 2014-04-17, Cesaretti et al.

3. Reference-by-reference analysis and § 102 mapping

Framework. Claim 1 requires, in one IC package: (a) four sensing elements; (b) four coils, one per element, wired so current flows in the same direction through all four; (c) an amplifier; (d) a back-bias magnet; (e) each coil multi-turn and wound in a single direction; and the steps of applying forward then reverse current through the coils, generating a first curve and a second curve of sensor output over time, combining them into normalized-sensitivity data that is "consistent over changes in an external field" (due at least in part to the back-bias magnet), storing it, and adjusting the absolute gain of the amplifier. Claim 15 is the device counterpart.

Bottom line up front: No single cited reference discloses the full combination of claim 1 or claim 15. The most relevant references disclose coil-based self-test / sensitivity-calibration of magnetic field sensors and storage of calibration values in memory — i.e., they anticipate or render obvious dependent claims and sub-features, and they are the natural § 103 combination partners. This is consistent with the prosecution history (final rejection 2019-03-19 → appeal → allowance 2022-05-19), i.e., the claims were allowed over these references.

Tier 1 — Most relevant (coil-driven sensitivity trimming / calibration)

1. US 7,923,996 B2 — Allegro MicroSystems — "Magnetic field sensor with automatic sensitivity adjustment"

• Filed 2008-02-26; granted 2011-04-12. (Cited by examiner.)
• Description: A magnetic field sensor in which a coil (or coils) couples a magnetic field to the sensing element(s); the sensor automatically adjusts its sensitivity using the coil-generated field, with calibration values used to trim gain. This is the closest conceptual forebear of the "drive a coil → measure output → trim gain" loop.
• § 102 relevance: Discloses the core of claim 1's "apply current through a coil → measure sensor output → adjust gain" and the integrated-coil-with-Hall-element feature → potentially anticipates claims 4, 17, and anticipates/is highly material to the "adjusting an absolute gain" step. It does not disclose four coils in same-direction current, bidirectional-current curves, or the back-bias-magnet-inside-package limitation; therefore it does not anticipate claim 1 or 15.

2. US 8,447,556 B2 (pub. US 2010/0211347 A1) — Allegro MicroSystems — "Circuits and methods for generating a self-test of a magnetic field sensor"

• Filed 2009-02-17; granted 2013-05-21 (pub. 2010-08-19). (Cited by examiner.)
• Description: A self-test current conductor/coil disposed proximate a magnetic field sensing element, including an explicit FIG. 2D four-element arrangement, driving self-test current pulses to generate a self-test field and a diagnostic output.
• § 102 relevance: Discloses a coil integrated with the sensing element, an IC package, and multi-element (incl. four-element) coil/sensing-element arrangements → material to claims 4, 7, 8, 17, 19. Does not disclose the same-direction four-coil wiring, bidirectional-current curve-combining, or a back-bias magnet inside the package → does not anticipate claim 1/15.

3. US 8,680,846 B2 (pub. US 2012/0274314 A1) — Allegro MicroSystems — "Circuits and methods for self-calibrating or self-testing a magnetic field sensor"

• Filed 2011-04-27; granted 2014-03-25 (pub. 2012-11-01). (Cited by examiner.)
• Description: Self-calibration/self-test using internal coils and signal processing to derive and store calibration data; includes gain/offset correction against a known coil-generated field.
• § 102 relevance: Coil-based calibration and sensitivity determination → material to claims 1 (in part), 4, 17. Not anticipatory of the full claim 1 combination.

4. US 2015/0022198 A1 — Allegro MicroSystems — "Method and apparatus for magnetic sensor producing a changing magnetic field"

• Filed 2013-07-19; published 2015-01-22.
• Description: A magnetic field sensor with an integrated coil that produces a changing magnetic field at the sensing element, used for self-test/calibration.
• § 102 relevance: Integrated coil producing a field at the sensing element for gain/output processing → material to claims 4, 17; potentially anticipatory of the "integrated coil" dependent claims. Not anticipatory of claim 1 (no four-coil/same-direction/bidirectional-curve combination).

5. US 2015/0301149 A1 — Allegro MicroSystems — "…self-calibrating or self-testing … using phase discrimination"

• Filed 2014-04-17; published 2015-10-22. (Same subject matter as the "Cesaretti et al." application U.S. 14/255,166 cited as non-patent literature #9.)
• Description: Self-calibration/self-test of a sensor using a coil-generated field and phase-discrimination signal processing to separate the self-test component from the measured field.
• § 102 relevance: Coil-driven calibration and signal-processing of the sensor output to derive a gain/trim value → material to claim 1 (preamble and gain-adjust step); not a full anticipator.

6. US 9,383,425 B2 — Allegro MicroSystems — "…current sensor having fault detection and self-test functionality"

• Filed 2012-12-28; granted 2016-07-05. (Cited by examiner.)
• Description: Coil-driven self-test of a current-sensing magnetic field sensor with fault detection and a memory for self-test results.
• § 102 relevance: Coil + Hall/field sensing + self-test + memory storage → material to claims 4, 8, 12, 19; not anticipatory of claim 1/15.

Tier 2 — Relevant to memory storage / gain trim / temperature trim (dependent-claim material)

Tier 3 — Third-party references (general background / obviousness context)

4. Synthesized § 102 conclusion

1. No cited reference anticipates independent claim 1 or independent claim 15. Each fails at least one essential limitation — most commonly (i) four coils wired so current flows in the same direction through all of them, (ii) multi-turn coils wound in a single direction, (iii) a back-bias magnet inside the same IC package as the trimming coils, and (iv) the two-curve (forward/reverse current) combination producing normalized-sensitivity data that is constant over external-field changes due to the back-bias magnet.

2. The references that come closest on § 102 — for the dependent claims — are the Allegro self-test/calibration family: US 7,923,996 B2; US 8,447,556 B2 (US 2010/0211347 A1); US 8,680,846 B2 (US 2012/0274314 A1); US 8,542,010 B2 (US 2011/0018533 A1); US 8,736,260 B2; US 9,383,425 B2; and US 2015/0022198 A1 / US 2015/0301149 A1 / US 2015/0176964 A1. These are the references most likely to be used individually to attack claims 4, 7, 8, 12, 17, 19 and to be combined for a § 103 attack on claim 1.

3. Third-party references (Super Dimension, Govari, AMI Semiconductor, Freescale, Everspin, AMS AG, Infineon) are background/context; on the record they do not anticipate any issued claim.

4. Procedural corroboration: The present citation set is consistent with the recorded prosecution (final rejection 2019-03-19; appeal 2021-04-22; appeal brief 2021-09-22; allowance 2022-05-19), i.e., the examiner's art was overcome and the claims were narrowed — reinforcing that none of these references read on the issued claim 1/claim 15 as a whole.

5. Flags, caveats, and cross-reference to earlier sections

• Caveat on the citation inventory: The text above reproduces the patent record's citation lists. I could not, within the tool budget, open the granted-PDF facsimile to verify the exact facsimile "(56) References Cited" subset; the two lists normally agree, but the examiner-cited versus applicant/IDS-cited distinction (the asterisk convention) is not fully recoverable from the text I have. Treat individual examiner/IDS attributions as approximate.
• Post-filing-date entries: Several items in the list (e.g., US 2016/0241186 A1, US 2016/0252599 A1, and especially US 2017/0336481 A1, filed 2016-05-23) postdate the 2015-07-17 filing date. US 2017/0336481 A1 in particular cannot be § 102 prior art against this patent. Their presence in the record indicates family/continuation or foreign-prosecution citation rather than US front-page prior art. This is a genuine anomaly worth noting rather than an error in the patent number.
• Consistency with earlier sections: This analysis agrees with, and builds on, the earlier "Patent summary" (issue date, claim count, narrowing to four elements) and the earlier "Litigation summary" (no litigation found naming US 11,402,440; the "Cited By"/"Families Citing" entries are later patents citing this family — not prior art and not litigation). No contradiction found.
• Reminder (per operating rules): No patent numbers were auto-corrected; e.g., US 9,383,425 B2 and US 8,447,556 B2 are reproduced exactly as they appear. If you want the definitive examiner-vs-third-party attribution and the exact facsimile (56) list, the authoritative source is the granted PDF at patentimages.storage.googleapis.com/.../US11402440.pdf (front page) and the USPTO PatentCenter file wrapper for application 14/801,997 (the IDS/PTO-892 forms).

If you'd like, I can next map the Tier 1/Tier 2 references against each of claims 2–14 and 16–22 in a formal element-by-element § 102/§ 103 chart.

I'll ground the analysis in the prior-art list on the patent page, and run a few targeted verifications on the key references before building the §103 case.

Let me verify a few more of the cited references that matter for the coil-drive and bidirectional-current elements.

Obviousness Analysis — U.S. Patent No. 11,402,440 B2 under 35 U.S.C. § 103

Building on the earlier-generated bibliographic, claim-overview, and litigation sections. Those sections are not repeated here.

0. Scope, sources, and confidence caveats

This analysis uses the "Prior Art" section of the Google Patents page for US 11,402,440 B2, which consists of exactly two lists:

1. Patent Citations (34) — references cited during prosecution.
2. Non-Patent Citations (9) — prosecution documents plus one co-pending U.S. application.

I deliberately exclude from the prior-art universe the following page sections, because they are not prior art to this patent (they post-date the 2015-07-17 effective filing date or are mere similarity lists):

• "Cited By (3)" — US 12,140,646; US 12,265,137; US 12,510,611 (later Allegro patents).
• "Families Citing this family (11)" — e.g., Melexis US 2021/0190893 A1 (priority 2017-10-06), TI US 11,061,100 B2 (priority 2019-06-12), Allegro US 11,630,130 B2 (priority 2021-03-31). All post-date.
• "Similar Documents" — e.g., US 11,680,996; US 10,761,120 — a similarity ranking, not a citation.

Confidence caveat: I verified full-text/abstract content for the principal references (the Allegro self-test/coil family, the Ami Semiconductor auto-calibration reference, and the Allegro temperature-trim reference) via search. For several of the 34 cited references I have only the title and the Google Patents entry, so my element-mapping for those is inferential and flagged as such. Where I say "does not appear to disclose," read it as "not found in the materials available to me," not as a proof of absence.

One further technical caveat that materially affects the §103 posture: this is an AIA patent (filed 2015-07-17, after March 16, 2013), so §102(a)(1)/(a)(2) apply, and §103 is measured against the AIA prior-art universe.

1. The reference set, with prior-art status and relevance tier

1.1 Tier 1 — Coil-plus-sensing-element in-package architectures (teach the apparatus)

1.2 Tier 2 — Bidirectional reference-field + arithmetic combining (teach the method)

1.3 Tier 3 — Storing trim and adjusting gain in memory/analog path (teach the back-end steps)

1.4 Post-filing citations (cannot be §102(a)(1) art; check §102(a)(2) individually)

• US 2016/0241186 A1 (Infineon, priority 2015-02-13, pub. 2016-08-18) — Stress compensated oscillator circuitry. Effectively filed before 2015-07-17, so potentially §102(a)(2) art; subject matter (oscillator stress compensation) appears not material to any claim element.
• US 2016/0252599 A1 (Infineon, priority 2015-02-27, pub. 2016-09-01) — Magnetic Field Sensor. Potentially §102(a)(2) art by its earlier effective filing date; content not verified in my searching — flag for follow-up, since an Infineon Hall-sensor reference could be relevant to claims 1–14.
• US 2017/0336481 A1 (Allegro, priority 2016-05-23, pub. 2017-11-23) — Gain equalization for multiple axis magnetic field sensing. Not prior art at all: both its publication date and its effective filing date post-date 2015-07-17. Its presence in the "Patent Citations (34)" list is an artifact (likely a later-cited/related document). Do not rely on it in a §103 case.

1.5 Non-patent citations

Of the nine, only "U.S. Appl. No. 14/255,166, Cesaretti et al." is a technical reference (discussed at Tier 2). The remainder — EPO examination report (2021-09-01), two EPO responses, PCT IPRP (2018-02-01), PCT Search Report and Written Opinion (2016-10-12), and two microprocessor-chapter excerpts (Sinclair, Electronics Simplified, Ch. 13; Overview of Microprocessors, Ch. 1) — are prosecution/§112 documents. The microprocessor chapters are notable because they were evidently cited to support a "processor/memory" enablement or §101-type position, not as technical prior art bearing on the magnetic-field-trimming subject matter.

2. Legal framework

Under Graham v. John Deere, obviousness turns on (i) the scope and content of the prior art, (ii) the differences between the prior art and the claims, (iii) the level of ordinary skill, and (iv) secondary considerations. Under KSR Int'l v. Teleflex, the analysis is expansive: a POSITA is "a person of ordinary creativity," and a combination may be obvious where the improvement is the "predictable use of prior art elements according to their established functions," or is the product of "ordinary innovation." A claim is not saved merely because the problem was newly recognized if the solution was known or obvious; KSR expressly rejected the Federal Circuit's rigid "teaching, suggestion, or motivation" test.

The relevant Graham/KSR rationales here are:

• (A) Combining prior-art elements according to known methods to yield predictable results.
• (B) Simple substitution of one known element for another.
• (C) Use of a known technique to improve a similar device in the same way.
• (D) Applying a known technique to a known device ready for improvement to yield predictable results.

3. Level of ordinary skill in the art (PHOSITA)

A POSITA here would hold a B.S. in electrical engineering (or equivalent) and ~2–4 years of experience designing Hall-effect/AMR magnetic field sensor ICs, including: familiarity with integrated trim/test coils; with spinning-current/chopping and differential Hall front-ends; with self-test and self-calibration architectures; and with the practice of storing gain/offset trim coefficients (EEPROM/PROM) and applying them through a gain-adjustable analog front end. That is exactly the profile the Tier 1–3 references themselves reflect.

4. Element decomposition of independent claim 1

5. Claim chart — mapping claim 1 onto the cited art

6. Proposed combinations and motivations

Combination I (primary) — US 2015/0022198 A1 + US 2008/0238410 A1 + US 2012/0086442 A1

What each contributes:

• US 2015/0022198 supplies the apparatus: a substrate-supported sensing element with an integrated coil in the same package, driven by the IC with a changing (i.e., bidirectional) current to impose a known field on the element.
• US 2008/0238410 supplies the method: drive the reference coil in two opposite polarities in successive sub-steps while the external field is present, measure the output each time, and combine/average the results to extract the calibration-field-responsive sensitivity term and thereby correct sensitivity drift.
• US 2012/0086442 supplies the back end: store gain/sensitivity coefficients in on-chip memory and apply them as a gain control signal to a gain-adjustable analog amplifier — and expressly for production trimming and temperature-coefficient handling.

Motivation to combine (KSR rationales A and D):
All three references sit in the same field (integrated Hall-effect sensor ICs; trim/self-calibration) and address the same known problem: how to establish sensor sensitivity accurately without an external field source. A POSITA seeking to improve trim accuracy of a back-biased sensor would naturally: (1) use the already-known integrated coil of US 2015/0022198 as the on-chip field source; (2) adopt Ami's opposite-polarity/averaging technique to make the measurement immune to the standing (back-bias) field, which cannot be removed in a packaged, back-biased part — indeed, the patent's own specification concedes the ferromagnetic/back-bias environment is not controllable in production test; and (3) write the resulting coefficient into the memory-and-gain-adjust architecture of US 2012/0086442. Each step is the predictable use of a known element for its established function, and the combination yields nothing more than the expected result (an accurate absolute-sensitivity trim).

§103 bottom line for Claim 1 under Combination I: a prima facie case of obviousness is made, with the caveat that no reference expressly states the "four-elements / same-direction coils / multi-turn / back-bias-in-package" structure as one package, so those elements rest on design-choice reasoning (see §10).

Combination II — US 7,923,996 B2 + US 2015/0022198 A1 + US 2012/0086442 A1

• US 7,923,996 alone already teaches coils proximate to the sensing element generating pulsed magnetic fields to directly measure sensitivity, plus a gain-adjustment circuit. It supplies elements 1a, 1b, 1j almost verbatim.
• US 2015/0022198 supplies the same-package integrated multi-turn coil and the changing (bidirectional) current drive.
• US 2012/0086442 supplies the memory + gain control back end.
• Motivation: using a bidirectional drive (routine, since US 2015/0022198 discloses alternating/ramped/pulsed currents and US 7,923,996 discloses pulsed fields) and averaging the two drive polarities is a predictable refinement to cancel common-mode (standing/external) field effects — the classic reason to take a differential/averaged measurement.

Strength: strong on 1a/1b/1j; weaker on 1h, because neither US 7,923,996 nor US 2015/0022198 is shown to disclose the combining of two opposite-drive curves to produce field-independent normalized sensitivity. Adding US 2008/0238410 or US 2015/0301149 repairs 1h.

Combination III — US 8,542,010 B2 + US 2015/0022198 A1 + US 2015/0185279 A1 + US 2012/0086442 A1

• US 8,542,010 (coils/conductors proximate to elements; multiplexing) + US 2015/0185279 (programmable/steerable self-test drive signals) supply the coil-drive-with-selectable-direction element, and both are same-field Allegro references.
• Motivation: "programmable self-test signals" that must be steered in polarity is the natural place to find bidirectional drive; and multiplexing/diagnostic switches (also shown in this family, and mirrored by the H-bridge switch topology of the patent's Fig. 12) make same-direction/opposite-direction selection a matter of switch control.

7. Independent device claim 15

Claim 15 is the apparatus mirror of claim 1, adding a coil driver circuit (apply first current in a first period; reverse current in a second period), a memory, and a signal processor (measure both periods, generate both curves, combine, store, adjust gain).

Mapping is essentially identical, with two reinforcements:

• The coil driver circuit is squarely met by US 2015/0022198's "integrated circuit 20 … configured to drive a changing current through coil 18," and by the H-bridge/diagnostic switching arrangements taught in the US 8,542,010 / US 2015/0185279 family.
• The signal processor + memory elements are met by US 2012/0086442 (segment processor + coefficient-table memory + gain control signal) and by US 2008/0238410 (which performs the arithmetic combining of opposite-polarity measurements to yield a corrected sensitivity).

Claim 15 conclusion: same prima facie obviousness posture as claim 1, with the same structural caveats.

8. Dependent claims 2–14 and 16–22

None of claims 2–14 or 16–22 adds a limitation that, on the available record, rescues the claims from the Combination I/II analysis. Claims 3/16 (averaging) are the most exposed, given Ami's express averaging teaching; claims 9/20 (pre-package coil-sensitivity determination) are the least supported by the cited art and are the strongest candidate for a non-obviousness argument on this record.

9. The patentee's best non-obviousness arguments (and responses)

A. "The prior art never recognized that coil sensitivity S_coil is itself a function of the external/back-bias field."
The specification is emphatic: "an assumption for the above was that S_coil is independent of the external magnetic field … However, this assumption has been found to be incorrect." Discovery of the source of a problem is generally not enough to confer patentability — KSR — if the solution was known or obvious. Ami's opposite-polarity-and-average technique is a known solution to the same class of error (measurement corrupted by a non-removable standing field). Response: the "recognition" argument is weak standing alone, but it becomes stronger when paired with argument B.

B. "The prior art does not teach or suggest averaging two oppositely-driven curves specifically to cancel back-bias-field dependence."
This is the patentee's strongest position on the record as I have it. Ami's averaging is aimed at isolating the calibration term from a uniform external field, and its discussion centers on sensitivity drift, not on the field-dependence of the coil's own effective sensitivity. If the patentee can show (e.g., via expert declaration) that a POSITA would not have expected coil sensitivity itself to vary with B_ext — i.e., that the technique was applied to a newly discovered, non-analogous error mechanism — this supports non-obviousness. Counter: under KSR, "[a] person of ordinary skill is also a person of ordinary creativity," and once the phenomenon is observed, averaging opposite-polarity measurements to cancel a field-proportional error is the most predictable remedy; the patent's own disclosure presents the combination as empirical ("measured using an illustrative magnetic sensor"), not as an unpredictable result.

C. "None of the cited art discloses the four-element / same-direction-coil / multi-turn / back-bias-in-package structure."
Partially true on the record. But this is a structural design-choice argument, and design choices (number of elements, coil turns, series vs. parallel interconnection) are classic §103 fodder, especially where the specification itself says the sensor "can include any practical number, including one, of magnetic field sensing elements." The specification's own breadth cuts against the patentee here.

D. Secondary considerations. No litigation, licensing, or commercial-success evidence is on the patent page; the patent's asserted ~1% absolute-trim accuracy and better temperature-coefficient trim could be argued as unexpected results, but the specification frames the accuracy as a design target met by calculation, not as a surprising outcome. Record is thin on secondary considerations. (Note the earlier "no litigation found" result was a negative search result, low confidence — do not treat it as conclusive.)

10. Summary judgment on obviousness

Overall: The claimed subject matter is, on the cited prior art, a combination of individually known elements performing their known functions with a predictable result — the archetype of KSR rationales (A) and (D). The single genuinely distinguishing insight (field-dependence of the integrated coil's own sensitivity, and its cancellation by averaging two oppositely-driven curves) is teachable from Ami and, once the phenomenon is observed, its remedy is an ordinary engineering step. The claims therefore face a credible §103 challenge, with the patentee's best (though not overwhelming) defenses being (i) the absence of an express same-structure teaching and (ii) the unprecedented recognition of the error mechanism — a classic "newly discovered problem" argument that KSR substantially devalues.

11. Open items I could not close (flagged, not asserted)

1. US 2016/0252599 A1 (Infineon, "Magnetic Field Sensor," priority 2015-02-27) — potentially available as §102(a)(2) art; content unverified. Worth checking, especially for claims 9/20.
2. Whether any cited reference discloses a rare-earth back-bias magnet integrated within the IC package — not confirmed in the materials I reviewed; this element is currently supported only by design-choice/Background knowledge.
3. The full texts of the ~20 Tier-3 references were not individually verified; my mappings there are inferential from titles and assignee practice.
4. Common-ownership disqualification under §102(b)(2)(C) for the Allegro-internal references (e.g., 14/255,166 → US 2015/0301149 A1) means several "Allegro self-test" citations cannot be used as §103 prior art even though they appear in the citation list — a point that both sides should confirm against the assignment records as of 2015-07-17 before relying on them.
5. The earlier "no litigation" finding remains low-confidence and does not bear on obviousness directly, but it means no secondary-considerations evidence (e.g., an injunction, damages award, or license) is available to rebut the prima facie case.