**United States Court of Appeals of the Federal Circuit**

02-1569,-1576

LINEAR TECHNOLOGY CORPORATION,

> Plaintiff/Counterclaimant-Appellant,

v\.

IMPALA LINEAR CORPORATION,

TOYODA AUTOMATIC LOOM WORKS, LTD., and ANALOG DEVICES, INC.,

> Defendants,

and

MAXIM INTEGRATED PRODUCTS, INC.,

> Defendant/Counterclaim Defendant-Cross Appellant,

and

UNITRODE CORPORATION,

> Defendant,

and

RONALD VINSANT,

> Counterclaim Defendant-Appellee.

[Alan H. Blankenheimer]{.underline}, Heller Ehrman White & McAuliffe
LLP, of San Diego, California, filed a combined petition for rehearing
and rehearing en banc for defendant/counterclaim defendant-cross
appellant, and counterclaim defendant-appellee. On the petition was
[Laura E. Underwood]{.underline}. Of counsel on the petition were [Chad
S. Campbell]{.underline} and [Dan L. Bagatell]{.underline}, Brown &
Bain, P.A., of Phoenix, Arizona.

[William K. West, Jr.]{.underline}, Howrey Simon Arnold & White, LLP, of
Washington, DC, filed a response to the petition for
plaintiff/counterclaimant-appellant. With him on the response was [David
W. Long]{.underline}.

[William P. Atkins]{.underline}, Pillsbury Winthrop LLP, of McLean,
Virginia, filed an amicus curiae brief for Intel Corporation. With him
on the brief was [Evan Finkel]{.underline}, of Los Angeles, California.

Appealed from: United States District Court for the Northern District of
California

Judge Vaughn R. Walker

#### United States Court of Appeals for the Federal Circuit

02-1569, -1576

LINEAR TECHNOLOGY CORPORATION,

> Plaintiff/Counterclaimant-Appellant,

v\.

IMPALA LINEAR CORPORATION,

TOYODA AUTOMATIC LOOM WORKS, LTD., and ANALOG DEVICES, INC.,

> Defendants,

and

MAXIM INTEGRATED PRODUCTS, INC.,

> Defendant/Counterclaim Defendant-Cross Appellant,

and

UNITRODE CORPORATION

> Defendant,

and

RONALD VINSANT,

> Counterclaim Defendant-Appellee.

ON PETITION FOR PANEL REHEARING AND REHEARING EN BANC

[ORDER]{.underline}

A combined petition for panel rehearing and rehearing en banc was filed
by Maxim Integrated Products, Inc. ("Maxim") and a response thereto was
invited by the court and filed by Linear Technology Corporation
("Linear"). An amicus curiae brief was filed by Intel Corporation.
Thereafter, these filings were referred to the merits panel that heard
the appeal.

Upon consideration thereof,

IT IS ORDERED THAT:

\(1\) The Petition for Panel Rehearing is granted for the limited
purpose of correcting this court's reporting of a portion of the
district court's decision.

\(2\) The previous opinion of the court in this appeal, issued on June
17, 2004 and reported at 371 F.3d 1364, is withdrawn and the opinion
attached to this order is substituted in its place.

\(3\) In all other respects, the Petition for Panel Rehearing is denied.

\(4\) The Petition for Rehearing En Banc is denied.

The mandate shall issue on August 24, 2004.

FOR THE COURT

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Date Jan Horbaly

Clerk

**United States Court of Appeals of the Federal Circuit**

02-1569,-1576

LINEAR TECHNOLOGY CORPORATION,

> Plaintiff/Counterclaimant-Appellant,

v\.

IMPALA LINEAR CORPORATION,

TOYODA AUTOMATIC LOOM WORKS, LTD., and ANALOG DEVICES, INC.,

> Defendants,

and

MAXIM INTEGRATED PRODUCTS, INC.,

> Defendant/Counterclaim Defendant-Cross Appellant,

and

UNITRODE CORPORATION,

> Defendant,

and

RONALD VINSANT,

> Counterclaim Defendant-Appellee.

[William K. West, Jr.]{.underline}, Howrey Simon Arnold & White, LLP, of
Washington, DC, argued for plaintiff/counterclaimant-appellant. With him
on the brief were [David W. Long]{.underline}, [Jenny W.
Chen]{.underline}, and [Pamela S. Kane]{.underline}.

[Alan H. Blankenheimer]{.underline}, Heller Ehrman White & McAuliffe
LLP, of San Diego, California, argued for defendant/counterclaim
defendant-cross appellant, and counterclaim defendant-appellee. On the
brief were [Chad S. Campbell]{.underline} and [Dan L.
Bagatell]{.underline}, Brown & Bain, P.A., of Phoenix, Arizona. Of
counsel was [Laura E. Underwood]{.underline}, Heller Ehrman White &
McAuliffe LLP, of San Diego, California.

Appealed from: United States District Court for the Northern District of
California

Judge Vaughn R. Walker

United States Court of Appeals for the Federal Circuit

02-1569, -1576

LINEAR TECHNOLOGY CORPORATION,

> Plaintiff/Counterclaimant-Appellant,

v\.

IMPALA LINEAR CORPORATION,

TOYODA AUTOMATIC LOOM WORKS, LTD., and ANALOG DEVICES, INC.,

> Defendants,

and

MAXIM INTEGRATED PRODUCTS, INC.,

> Defendant/Counterclaim Defendant-Cross Appellant,

and

UNITRODE CORPORATION

> Defendant,

and

RONALD VINSANT,

> Counterclaim Defendant-Appellee.

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

REVISED OPINION ISSUED: August 17, 2004

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Before NEWMAN, SCHALL, and LINN, [Circuit Judges]{.underline}.

LINN, [Circuit Judge]{.underline}.

A petition for panel rehearing was filed by Maxim and granted by the
panel for the limited purpose of correcting this court's reporting of
the district court's decision on Linear's motion for summary judgment
that Vinsant was not an inventor of the '178 patent. This opinion
replaces the court's original opinion in response to the petition for
rehearing. The disposition of the appeal is unchanged.

Linear Technology Corporation ("Linear") appeals from a decision of the
United States District Court for the Northern District of California, in
Civil Action No. 98‑CV‑1727, granting summary judgment of
non-infringement in favor of defendant Maxim Integrated Products, Inc.
("Maxim") with respect to Linear's U.S. Patent No. 5,481,178 ("the '178
patent"). Maxim conditionally cross-appeals the district court's entry
of summary judgment that Ronald Vinsant was not an inventor of the '178
patent. Because the district court erred in construing the "circuit" and
"circuitry," "vary the duty cycle," and "simultaneously off" claim
limitations of the '178 patent, we vacate the judgment of
non-infringement and remand for further consideration. Because genuine
issues of material fact have been raised concerning Maxim's contributory
infringement or inducement, we vacate the district court's summary
judgment of no contributory infringement or inducement of the current
reversal method claims of the '178 patent. Because Maxim failed to raise
a genuine issue of material fact, the matter of inventorship was
amenable to determination on summary judgment on the undisputed factual
premises. On these premises, the district court correctly held that
Vinsant was not a joint inventor of the '178 patent.

I. BACKGROUND

This appeal relates to voltage regulators, which are designed to provide
a predetermined and constant voltage output from a fluctuating input
voltage source, such as a battery, to an energy consuming device, called
a "load." Voltage regulators of the "switching" type use transistors,
which are turned on and off like switches, to control the electrical
power supplied by a power source. '178 patent, col. 1, ll. 20-24.
Switching voltage regulators transmit power to the load in discrete
current pulses. [Id.]{.underline} at col. 1, ll. 27-28. To ensure a
steady flow of current pulses, control circuitry is used to turn the
transistors on and off. [Id.]{.underline} at col. 1, ll. 31-33.
Selectively turning the transistors off advantageously reduces the power
dissipated in the regulator itself, yielding higher efficiencies for
switching voltage regulators as compared to other regulator designs.
[See]{.underline} [id.]{.underline} at col. 1, ll. 39-41;
[id.]{.underline} at col. 1, ll. 48-50. The '178 patent discloses a
"sleep mode" where both switching transistors are turned off to
additionally reduce the power consumed by the regulator itself to
further improve the regulator's efficiency. [Id.]{.underline} at col. 5,
ll. 59-66. Also disclosed is a current reversal prevention mode where
the regulator prevents the reverse flow of electrical current to
forestall power from being drained from the load. [Id.]{.underline} at
col. 14, ll. 1-10.

Independent claim 1 is representative of a "sleep mode" claim of the
'178 patent, and is reproduced below with the disputed limitations
highlighted:

> 1\. A circuit for controlling a switching voltage regulator, the
> regulator having (1) a switch circuit coupled to receive an input
> voltage and including a pair of synchronously switched switching
> transistors and (2) an output circuit including an output terminal and
> an output capacitor coupled thereto for supplying current at a
> regulated voltage to a load, the control circuit comprising:
>
> a [first circuit]{.underline} for monitoring a signal from the output
> terminal to generate a first feedback signal;
>
> a [second circuit]{.underline} for generating a [first control
> signal]{.underline} during a first state of circuit operation, [the
> first control signal]{.underline} being responsive to the first
> feedback signal [to vary the duty cycle of the switching
> transistors]{.underline} to maintain the output terminal at the
> regulated voltage; and
>
> a [third circuit]{.underline} for generating a second control signal
> during a second state of circuit operation [to cause both switching
> transistors to be simultaneously OFF for a period of time]{.underline}
> if a sensed condition of the regulator indicates that the current
> supplied to the load falls below a threshold fraction of maximum rated
> output current for the regulator, whereby operating efficiency of the
> regulator at low output current levels is improved.

[Id.]{.underline} at col. 16, ll. 34-57 (emphases added). Asserted
independent claims 34, 41, 55, and 57 are also "sleep mode" claims.

Independent claim 51 is exemplary of a current reversal prevention mode
claim, and is reproduced below:

> 51\. A method for controlling a switching voltage regulator, the
> regulator having (1) a switch circuit coupled to receive an input
> voltage and including a pair of synchronously switched switching
> transistors and (2) an output circuit including an output terminal and
> an output inductor coupled thereto for supplying current at a
> regulated voltage to a load, the method comprising the steps of:
>
> \(a\) monitoring a signal from the output terminal to generate a first
> feedback signal;
>
> \(b\) varying the duty cycle of the switching transistors in response
> to the first feedback signal to maintain the output terminal at the
> regulated voltage during a first state of circuit operation, wherein
> the current to the load has a polarity; and
>
> \(c\) maintaining one of said switching transistors OFF for a period
> of time following the first state of circuit operation to de-couple
> the output circuit from ground during the period of time so as [to
> prevent the current to the load from reversing polarity]{.underline}.

[Id.]{.underline} at col. 21, ll. 9-27 (emphasis added).

In 1997, Linear sued Maxim; Impala Linear Corporation ("Impala"); Toyoda
Automatic Loom Works, Ltd. ("Toyoda"); Analog Devices, Inc. ("Analog");
and Unitrode Corporation ("Unitrode"), all manufacturers of switching
voltage regulators, for infringement of claims 1-3, 31-35, 41, and 55-57
(the sleep mode claims) and claims 44-48 and 51-54 (the current reversal
claims) of the '178 patent. On June 9, 1999, the district court issued a
claim construction order construing all asserted claims of the '178
patent. [Linear Tech. Corp. v. Impala Linear Corp.]{.underline}, No.
C-98-1727-FMS (N.D. Cal. June 9, 1999) ("[Claim Construction
Order]{.underline}"). On September 21, 2001, a different district court
judge issued an order granting summary judgment of non-infringement in
favor of Maxim and granting Linear's motion for summary judgment that
Vinsant was not an inventor of the '178 patent. [Linear Tech. Corp. v.
Impala Linear Corp.]{.underline}, No. C‑98‑1727‑VRW (N.D. Cal. Sep. 21,
2001) ("[Summary Judgment Order]{.underline}"). Some of the original
claim constructions in the Claim Construction Order were modified in the
subsequent Summary Judgment Order. On October 26, 2001, the district
court entered final judgments under Rule 54(b) concerning Unitrode,
Maxim, and Vinsant and, given the interest of Analog in the claim
constructions, issued an Order certifying an interlocutory appeal of the
claim construction determinations under 28 U.S.C. § 1292(b).

Following the October 26, 2001 order, Linear and Analog sought leave of
this court for permission to proceed with an interlocutory appeal of the
district court's claim constructions under 28 U.S.C. § 1292(b). We
denied their request and also dismissed the appeals from the Rule 54(b)
final judgments as to Unitrode, Maxim, and Vinsant. [Linear Tech. Corp.
v. Impala Linear Corp.]{.underline}, 31 Fed. Appx. 700 (Fed. Cir. 2002).

Following dismissal by this court, Linear and Analog stipulated to
dismiss Linear's claims against Analog without prejudice, and the
remaining parties sought re‑entry of the Rule 54(b) judgments as to
them. On July 26, 2002, the district court entered a new final judgment
of non-infringement in favor of Maxim, Unitrode, and Vinsant, and
certified the judgment under Rule 54(b). In the interim, Linear settled
with Unitrode, and this court granted a joint motion to dismiss
Unitrode's appeal. [Linear Tech. Corp. v. Impala Linear
Corp.]{.underline}, 64 Fed. Appx. 226 (Fed. Cir. 2003). This left Maxim
and Vinsant as the only remaining adverse parties in this litigation.

Linear again appealed. Maxim objects to the district court's
certification of the Rule 54(b) judgments without imposing a condition
barring Linear from bringing Analog back into the case at a future
point. Maxim argues that Linear is likely to revive its claims against
Analog once the appeal to this court is resolved, and that this matter
should be dismissed for lack of jurisdiction unless Linear commits not
to rejoin Analog in the event of a remand. Further, Maxim claims that
Linear's actions are potentially an evasion of our previous order
dismissing the case due to improper certification under Rule 54(b),
[see]{.underline} [Linear Tech.]{.underline}, 31 Fed. Appx. at 703,
because this appeal is "virtually identical" to the appeal this court
previously rejected. Maxim contends that the new Rule 54(b) judgments
are merely an attempt to manufacture appellate jurisdiction.

Maxim's argument overlooks a critical point. Unlike the prior appeal,
Analog is no longer a party to the litigation. In the prior appeal,
Analog remained a party to the litigation with Linear's unresolved
infringement claims pending against it, while the other defendants
litigated the district court's claim constructions and summary judgments
of non-infringement. [See]{.underline} [Linear Tech.]{.underline}, 31
Fed. Appx. at 702. Linear has settled with, or stipulated to the
dismissal of its claims with, all of the parties except Maxim and
Vinsant. Proper Rule 54(b) judgments have been entered concerning Maxim
and Vinsant. Linear's claims against Analog have been dismissed without
prejudice; Analog is no longer a party to this appeal; and Linear's
dispute as to Analog has ended, with consequences to Linear, such as the
running of the statute of limitations on damages. A dismissal without
prejudice is nonetheless a final, appealable judgment. [United States v.
Wallace & Tiernan Co.]{.underline}, 336 U.S. 793, 795 n.1 (1949) ("That
the dismissal was without prejudice to filing another suit does not make
the cause unappealable, for denial of relief and dismissal of the case
ended this suit so far as the District Court was concerned.").

Because Linear has now presented us with a final, appealable judgment,
we have jurisdiction pursuant to 28 U.S.C. § 1295(a)(1).

II\. ANALYSIS

A. Standard of Review

"We review the grant of summary judgment de novo, drawing all reasonable
inferences in favor of the non-moving party." [Teleflex, Inc. v. Ficosa
N. Am. Corp.]{.underline}, 299 F.3d 1313, 1323 (Fed. Cir. 2002) (citing
[Anderson v. Liberty Lobby, Inc.]{.underline}, 477 U.S. 242, 255
(1986)). When evaluating a motion for summary judgment, we view the
record evidence through the same evidentiary standard that would prevail
at trial. [Eli Lilly & Co. v. Barr Labs., Inc.]{.underline}, 251 F.3d
955, 962 (Fed. Cir. 2001). Summary judgment is only appropriate if there
are no genuine issues of material fact and the movant is entitled to
judgment as a matter of law. [SRI Int'l v. Matsushita Elec.
Corp.]{.underline}, 775 F.2d 1107, 1116 (Fed. Cir. 1985) (en banc).

Claim construction is a question of law reviewed de novo. [Ferguson
Beauregard v. Mega Sys., Inc.]{.underline}, 350 F.3d 1327, 1338 (Fed.
Cir. 2003). Whether claim language should be interpreted as a
means-plus-function limitation under 35 U.S.C. § 112 ¶ 6 is a question
of law. [Personalized Media Communications v. Int'l Trade
Comm'n]{.underline}, 161 F.3d 696, 702 (Fed. Cir. 1998). If § 112 ¶ 6 is
applicable, the determination of the corresponding structure is also a
question of law. [Kemco Sales, Inc. v. Control Papers Co.]{.underline},
208 F.3d 1352, 1360 (Fed. Cir. 2000). Infringement, whether literal or
under the doctrine of equivalents, is a question of fact.
[Ferguson]{.underline}, 350 F.3d at 1338.

Inventorship is a question of law reviewed de novo, based on underlying
findings of fact. [See]{.underline} [Univ. of Colo. Found., Inc. v. Am.
Cyanamid Co.]{.underline}, 342 F.3d 1298, 1304 (Fed. Cir. 2003). A party
seeking correction of inventorship must provide clear and convincing
evidence of inventorship. [Hess v. Advanced Cardiovascular Sys.,
Inc.]{.underline}, 106 F.3d 976, 979-80 (Fed. Cir. 1997).

B. Main Appeal

1\. "Circuit" and "Circuitry" Limitations

The parties dispute whether the "circuit" and "circuitry" limitations in
independent claims 1, 44, 55, and 57 of the '178 patent are
means-plus-function limitations subject to 35 U.S.C. § 112 ¶ 6. Claim 1
is illustrative, and we reiterate the language of that claim with the
relevant limitations highlighted:

> 1\. A circuit for controlling a switching voltage regulator . . . the
> control circuit comprising:
>
> a [first circuit]{.underline} for monitoring a signal from the output
> terminal to generate a first feedback signal;
>
> a [second circuit]{.underline} for generating a first control signal
> during a first state of circuit operation, the first control signal
> being responsive to the first feedback signal to vary the duty cycle
> of the switching transistors to maintain the output terminal at the
> regulated voltage; and
>
> a [third circuit]{.underline} for generating a second control signal
> during a second state of circuit operation to cause both switching
> transistors to be simultaneously OFF for a period of time if a sensed
> condition of the regulator indicates that the current supplied to the
> load falls below a threshold . . . .

'178 patent, col. 16, ll. 35-57 (emphasis added). Rejecting Linear's
expert testimony that the word "circuit" used in the claim would be
understood by persons of ordinary skill in the art to connote sufficient
structure to perform the recited function, the district court ultimately
concluded that these limitations were means-plus-function limitations
subject to 35 U.S.C. § 112 ¶ 6. [Claim Construction Order]{.underline},
slip op. at 2-3. The district court remarked that the only recitation of
structure in the claim was in the preamble. [Id.]{.underline} at 4.

Linear argues that the district court legally erred in failing to apply
the presumption that § 112 ¶ 6 does not apply if the word "means" is not
present in the limitation. Further, Linear contends that the district
court erred in disregarding Linear's expert evidence that persons
skilled in the art would understand the word "circuit" to connote the
structure needed to perform the operations recited by the claim
language. Maxim responds that § 112 ¶ 6 was correctly applied to these
limitations because "circuit" and "circuitry" are too generic to provide
sufficient structure to avoid the application of § 112 ¶ 6.

Our precedent has established that "\[a\] claim limitation that actually
uses the word 'means' will invoke a rebuttable presumption that § 112
¶ 6 applies. By contrast, a claim term that does not use 'means' will
trigger the rebuttable presumption that § 112 ¶ 6 does not apply." [CCS
Fitness, Inc. v. Brunswick Corp.]{.underline}, 288 F.3d 1359, 1369 (Fed.
Cir. 2002) (internal citation omitted); [see also]{.underline}
[Personalized Media]{.underline}, 161 F.3d at 703.

Because none of the disputed limitations include the word "means," the
district court legally erred by failing to apply the rebuttable
presumption that § 112 ¶ 6 does not apply. The district court should
have imposed on Maxim, who advocated a construction under § 112 ¶ 6, the
burden of overcoming the presumption by demonstrating that the claim
fails to "recite sufficiently definite structure" or recites a "function
without reciting sufficient structure for performing that function."
[Watts v. XL Sys., Inc.]{.underline}, 232 F.3d 877, 880 (Fed. Cir.
2000); [see also]{.underline} [Apex Inc. v. Raritan Computer,
Inc.]{.underline}, 325 F.3d 1364, 1371-72 (Fed. Cir. 2003) ("\[A\] claim
term that does not use 'means' will trigger the rebuttable presumption
that § 112, ¶ 6 does not apply. . . . \[The party alleging that § 112,
¶ 6 applies in the absence of a 'means' claim term\] can rebut this
presumption if it demonstrates that the claim term fails to recite
sufficiently definite structure or else recites a function without
reciting sufficient structure for performing that function." (internal
citations and quotation marks omitted)); [CCS Fitness]{.underline}, 288
F.3d at 1369. Instead, the district court placed on Linear the burden to
establish that the claim recited sufficient structure. [See,
e.g.]{.underline}, [Claim Construction Order]{.underline}, slip op. at 3
("The Court finds that \[Linear's expert\] Dr. Blauschild's definition
of 'circuit' does not recite sufficient structure for purposes of § 112
¶ 6.").

"To help determine whether a claim term recites sufficient structure, we
examine whether it has an understood meaning in the art." [CCS
Fitness]{.underline}, 288 F.3d at 1369. Technical dictionaries, which
are evidence of the understandings of persons of skill in the technical
arts, plainly indicate that the term "circuit" connotes structure.
[See]{.underline} [Tex. Digital Sys., Inc. v. Telegenix,
Inc.]{.underline}, 308 F.3d 1193, 1202 (Fed. Cir. 2002) ("Dictionaries
are always available to the court to aid in the task of determining
meanings that would have been attributed by those of skill in the
relevant art to any disputed terms used by the inventor in the
claims."). For example, [The Dictionary of Computing]{.underline} 75
(4th ed. 1996) defines "circuit" as "the combination of a number of
electrical devices and conductors that, when interconnected to form a
conducting path, fulfill some desired function." [See]{.underline}
Rudolf F. Graf, [Modern Dictionary of Electronics]{.underline} 116 (7th
ed. 1999) (defining "circuit" as "\[t\]he interconnection of a number of
devices in one or more closed paths to perform a desired electrical or
electronic function"). Thus, when the structure-connoting term "circuit"
is coupled with a description of the circuit's operation, sufficient
structural meaning generally will be conveyed to persons of ordinary
skill in the art, and § 112 ¶ 6 presumptively will not apply.
[See]{.underline} [Apex]{.underline}, 325 F.3d at 1373 ("\[T\]he term
'circuit' with an appropriate identifier such as 'interface,'
'programming' and 'logic,' certainly identifies some structural meaning
to one of ordinary skill in the art.").

This is exemplified by the claim language in the '178 patent. Claim 1
recites: "a first circuit for monitoring a signal from the output
terminal to generate a first feedback signal." '178 patent, col. 16, ll.
42-43. The contextual language describes the objective of the "circuit,"
"monitoring a signal from the output terminal," and the desired output
of the "circuit," "generat\[ing\] a first feedback signal." The "second
circuit" and "third circuit" limitations in claim 1 are accompanied by
similar language reciting their respective objectives or operations.
[See]{.underline} [id.]{.underline} at col. 16, ll. 44-57. That persons
of ordinary skill in the art would understand the structural
arrangements of circuit components from the term "circuit" coupled with
the qualifying language of claim 1 was recognized by Linear's expert
witness. [See]{.underline} [Claim Construction Order]{.underline}, slip
op. at 2-3 (quoting the declaration of Dr. Blauschild that a person of
ordinary skill in the art reading the claims "would have an
understanding of, and would be able to draw, structural arrangements of
the circuit elements defined by the claims."); [see also]{.underline}
[Apex]{.underline}, 325 F.3d at 1374 ("Moreover, every use of the term
\['circuit'\] in the asserted claims includes additional adjectival
qualifications further identifying sufficient structure to perform the
claimed functions to one of ordinary skill in the art.").

We hold that because the term "circuit" is used in each of the disputed
limitations of claims 1, 44, 55, and 57 of the '178 patent with a
recitation of the respective circuit's operation in sufficient detail to
suggest structure to persons of ordinary skill in the art, the "circuit"
and "circuitry" limitations of such claims are not means-plus-function
limitations subject to 35 U.S.C. § 112 ¶ 6. The district court's holding
to the contrary was an error of law.

2\. PWM Circuits as Corresponding Structure to "Vary the Duty Cycle"

All asserted apparatus claims except claim 41 (claims 1-3, 31-35, 44-48,
and 55-57) include limitations concerning "vary\[ing\] the \[regulator\]
duty cycle" that were analyzed by the district court under § 112 ¶ 6.
The parties dispute whether pulse width modulation ("PWM") mentioned in
the written description should have been considered as structure
corresponding to the "vary\[ing\] the duty cycle" functional language of
the claims in the district court's claim construction. [See]{.underline}
[B. Braun Med., Inc. v. Abbott Labs.]{.underline}, 124 F.3d 1419, 1424
(Fed. Cir. 1997) ("\[S\]tructure disclosed in the specification is
'corresponding' structure only if the specification or prosecution
history clearly links or associates that structure to the function
recited in the claim. This duty to link or associate structure to
function is the quid pro quo for the convenience of employing § 112,
¶ 6.").

Because we have held that the "circuit" and "circuitry" limitations of
independent claims 1, 44, 55, and 57 are not subject to 35 U.S.C. § 112
¶ 6, only independent claim 34, and its dependent claim 35, have a
means-plus-function limitation remaining at issue. The disputed
limitation of claim 34 provides:

> a [second means]{.underline} for generating a first control signal
> during a first state of circuit operation, the first control signal
> being responsive to the voltage feedback signal [to vary the duty
> cycle of the switching transistors]{.underline} to maintain the output
> terminal at the regulated voltage . . . .

'178 patent, col. 19, ll. 15-19 (emphases added).

The parties do not dispute that the constant off-time circuit depicted
in the Figures of the '178 patent is corresponding structure. Linear
argues the district court erred in finding on summary judgment that the
PWM circuit was "essentially generic" and thus was not corresponding
structure for the sleep mode limitations. Linear argues that PWM
circuits are not generic, but instead identify a specific class of
structures, which is sufficient under § 112 ¶ 6. Maxim responds that the
expression "pulse width modulation" refers to the function performed by
circuits that control regulator output, but does not describe an actual
circuit or structure for performing that function. It contends that
passages in the '178 patent specification discussing PWM circuits cannot
be corresponding structure because they describe only function, and
describe no particular structure.

The district court's initial claim construction ruling stated that PWM
circuits were corresponding structure to the "vary the duty cycle"
limitation of claim 34. [Claim Construction Order]{.underline}, slip op.
at 22. On summary judgment, the district court modified its earlier
ruling, stating that PWM circuits were not corresponding structure for
these limitations. [Summary Judgment Order]{.underline}, slip op. at
23-24. Relying on deposition testimony by the named inventor, Dr.
Wilcox, the district court found that "the term 'pulse-width modulator'
is essentially generic" and "does not reference a specific structure."
[Id.]{.underline} at 24.

"The determination of the claimed function and corresponding structure
of a means-plus-function claim limitation is a question of law, reviewed
de novo." [ACTV Inc. v. Walt Disney Co.]{.underline}, 346 F.3d 1082,
1087 (Fed. Cir. 2003). In construing a means-plus-function claim
limitation, the recited function within that limitation must first be
identified. [Id.]{.underline} "Then, the written description must be
examined to determine the structure that corresponds to and performs
that function." [Id.]{.underline} "Proper application of § 112 ¶ 6
generally reads the claim element to embrace distinct and alternative
described structures for performing the claimed function." [Creo Prods.,
Inc. v. Pressteck, Inc.]{.underline}, 305 F.3d 1337, 1346 (Fed. Cir.
2002).

The claim language states that the function of the "second means"
limitation in claim 34 is to generate a first control signal to vary the
duty cycle of the switching transistors to maintain the output terminal
at the regulated voltage. [See]{.underline} '178 patent, col. 19, ll.
15‑19. As the district court correctly recognized in its claim
construction order, [Claim Construction Order]{.underline}, slip op. at
22, the '178 patent specification links the structure of PWM circuitry
to the function of controlling the duty cycle of the switching
transistors in the following passage:

> As discussed above, the embodiments of the control circuits of the
> present invention shown in FIGS. 2-4 include one-shot circuit 25. [In
> accordance with another feature of the present invention, the one-shot
> circuit could be replaced with other types of circuits that control
> the duty cycle of the power switch. For example, one-shot circuit 25
> could be replaced with a pulse-width modulator circuit that provides a
> pulse-width modulated signal in response to a control
> signal.]{.underline} Of course, other types of circuits could be used
> as well.

'178 patent, col. 9, ll. 12-22 (emphasis added).

Contrary to Maxim's argument, and the district court's conclusion on
summary judgment, PWM circuits are not excludable from the corresponding
structure for failing to reference a specific structure.
[See]{.underline} [Summary Judgment Order]{.underline}, slip op. at 24.
Although the expression "PWM circuit" does not reference a specific
circuit structure, persons of skill in the art would understand that
"PWM circuit" references a discrete class of circuit structures that
perform known functions. That the disputed term is not limited to a
single structure does not disqualify it as a corresponding structure, as
long as the class of structures is identifiable by a person of ordinary
skill in the art. [See]{.underline} [Creo Prods.]{.underline}, 305 F.3d
at 1347 ("Under our case law interpreting § 112, ¶ 6, knowledge of one
skilled in the art can be called upon to flesh out a particular
structural reference in the specification for the purpose of satisfying
the statutory requirement of definiteness."). Linear cites technical
textbooks and electronic parts catalogs indicating that PWM circuits are
well-known circuit structures to persons of skill in the art. Thus, we
conclude that the district court erred in excluding PWM circuits from
the corresponding structure of the "second means" limitation of claim 34
of the '178 patent.

3\. "Simultaneously Off"

The parties dispute whether the "simultaneously off" sleep mode
limitations of claims 1-6, 31-33, 34-35, 41, and 57 of the '178 patent
were correctly construed. The relevant limitations of the independent
claims of the '178 patent provide:

> (claim 1) a third circuit for generating a second control signal
> during a second state of circuit operation [to cause both switching
> transistors to be simultaneously OFF for a period of time]{.underline}
> if a sensed condition of the regulator indicates that the current
> supplied to the load falls below a threshold fraction of maximum rated
> output current for the regulator, whereby operating efficiency of the
> regulator at low output current levels is improved.

'178 patent, col. 16, ll. 49-57 (emphasis added).

> (claim 34) a third means for generating a second control signal during
> a second state of circuit operation [to cause both switching
> transistors to be simultaneously OFF for a period of time]{.underline}
> if a sensed condition of the regulator indicates that the current
> supplied to the load falls below a threshold fraction of maximum rated
> output current for the regulator, the period of time having a duration
> which is a function of the current supplied to the load by the
> regulator.

[Id.]{.underline} at col. 19, ll. 20-27 (emphasis added).

> (claim 41) [turning both switching transistors simultaneously OFF for
> a period of time]{.underline} during a second state of circuit
> operation following the first state of circuit operation, so as to
> allow the output capacitor to maintain the output substantially at the
> regulated voltage by discharging during the second state of circuit
> operation, the period of time beginning when the current supplied to
> the load falls below a threshold fraction of maximum rated output
> current for the regulator, and having a duration which is a function
> of the current supplied to the load by the regulator . . . .

[Id.]{.underline} at col. 20, ll. 5-14 (emphasis added).

> (claim 57) circuitry incorporated in the control circuit for detecting
> a condition in the output circuit indicative of the current supplied
> to the load falling below a threshold fraction of maximum rated output
> current for the regulator and for [turning off both switching
> transistors simultaneously for a period of time]{.underline} if the
> supplied current falls below the threshold, the period of time having
> a duration which is a function of the current supplied to the load by
> the regulator.

[Id.]{.underline} at col. 22, ll. 41-49 (emphasis added).

Linear argues that the district court misconstrued these limitations and
erred in not giving the claim term "simultaneously off" the full range
of its ordinary and customary meaning by requiring that the transistors
be switched off at the same moment. Linear argues that the correct
construction refers to the action of the circuit in holding both
transistors off at the same time. In support of its construction, Linear
points to the following passage in the '178 patent specification:

> \[C\]onstant current source I~1~ 72 and comparator 74 allow push-pull
> switch 15 to go into a [state of operation where both MOSFETS 16 and
> 17 are simultaneously OFF]{.underline} under conditions where the
> output voltage V~OUT~ can be maintained substantially at the regulated
> voltage V~REG~ by output capacitor C~OUT~. [This state of operation is
> referred to herein as a "sleep mode."]{.underline} The ability of
> push-pull switch 15 to go into such a sleep mode is in contrast to the
> regulator circuit of FIG. 1 where one of the two MOSFETs 16 and 17 is
> substantially ON at all times. This feature of the present invention
> reduces the regulator circuit power consumption since push-pull switch
> 15 does not dissipate power or allow power to be pulled from load R~L~
> to ground in sleep mode.

'178 patent, col. 5, l. 59 -- col. 6, l. 5 (emphases added). Linear
argues that the plain meaning of "simultaneously" merely requires a
condition existing or occurring at the same time. It thus contends that
the limitation "simultaneously off" only requires both transistors to be
off at the same time, regardless of when each transistor is turned off
or whether one transistor is turned off before the other.

Maxim responds that these limitations are directed to the manner in
which sleep mode is entered. In amending its claims to distinguish the
prior art, the applicant stated "the switching transistors of
applicants' regulator are turned off if the current supplied to the load
[falls below]{.underline} a threshold level." In describing the sleep
mode claims in response to a rejection, applicant stated: "When the
output current of the regulator drops below a threshold level . . . the
regulator's switching transistors are turned off simultaneously for a
period of time while previously stored energy in the regulator's output
circuit supplies current to the load."

In construing the claims, the district court relied on the definition of
"simultaneous" from [Webster's Ninth New Collegiate
Dictionary]{.underline} 1099 (1991): "existing or occurring at the same
time; exactly coincident." [Claim Construction Order]{.underline}, slip
op. at 11. The district court found this definition to suggest that an
action was required. The court thus construed the term to encompass "the
act of turning or causing both transistors to be off, not the state of
being off, that occurs simultaneously." [Id.]{.underline}

The plain meaning of the word simultaneously is "in a simultaneous
manner : at the same time : [concurrently]{.smallcaps}." [Webster's
Third New International Dictionary]{.underline} 2122 (1993). The
definition of simultaneous is "[existing or occurring]{.underline} at
the same time : [coincident, concurrent]{.smallcaps}." [Id.]{.underline}
(emphasis added). Because simultaneously merely requires a condition to
exist at the same time or concurrently, the district court erroneously
construed the "simultaneously off" limitations too narrowly. The
disputed limitation in claims 1 and 34 "to cause both switching
transistors to be simultaneously OFF for a [period of time]{.underline}"
does not require the switching transistors to be turned off or disabled
at the same instant, as the district court held. (emphasis added). To
construe the term in that way overlooks the phrase "period of time,"
which refers to a span of time more consistent with the recitation of a
state of operation of the transistors rather than an act of transition
between states. Thus, we conclude that the ordinary and customary
meaning of "simultaneously off," in contextual relation to the "period
of time" language of the claims, encompasses the simultaneous state of
both switching transistors being disabled or held off. The parallel
provisions in claims 44 and 57, e.g., "turning both switching
transistors simultaneously OFF for a period of time," do not merit a
different construction. The applicant did not disavow the broader
meaning of "simultaneously off" in the specification or prosecution
history. The passages in the prosecution history cited by Maxim are not
disclaimers of claim scope meriting a narrower construction, but are
instead consistent with our claim construction of "simultaneously off."

Thus, the "simultaneously off" limitations of claim 1, 34, 44, and 57
only require that both switching transistors be held off or disabled for
an overlapping period of time. The switching transistors do not need to
be turned off or disabled at the same instant. The district court erred
in construing the claims to the contrary.

4\. Contributory Infringement or Inducement of Current Reversal Method
Claims

The parties dispute whether Linear presented sufficient evidence to find
direct infringement by Maxim's customers to support its claim of
contributory infringement or inducement of the current reversal method
claims 51-54 of the '178 patent by Maxim. The parties' dispute centers
around step (c) of claim 51, which states in pertinent part:

> maintaining one of said switching transistors OFF for a period of time
> following the first state of circuit operation to de-couple the output
> circuit from ground during the period of time so as [to prevent the
> current to the load from reversing polarity]{.underline}.

'178 patent, col. 21, ll. 24-29 (emphasis added). The district court
construed this limitation as follows:

> Th\[e\] purpose \[of the current reversal protection feature\] is to
> prevent the regulator from [drawing power from the load]{.underline}.
> As far as the Court is aware, power is not drawn from the load just
> because the 'saw tooth' current dips below a value of zero. Rather,
> [because the average inductor current is designed to match the output
> current, the relevant measure of when the regulator draws power from
> the load is when the average (not instantaneous) current reverses
> polarity.]{.underline}

[Claim Construction Order]{.underline}, slip op. at 35 (second emphasis
added). Linear does not appeal this construction.

On summary judgment, the district court concluded that for Maxim to
infringe limitation (c) of claim 51, which requires prevention of the
average inductor current from reversing polarity, Maxim's accused
circuits must be used with a load capable of creating a reverse average
inductor current. [Summary Judgment Order]{.underline}, slip op. at 29.
In support of its allegation of infringement, Linear submitted an expert
declaration by Robert Blauschild (the "RB I" declaration) stating that
Maxim's accused circuits were used in computers made by two of Maxim's
customers. [Id.]{.underline} at 31. But Blauschild's "RB I" expert
declaration was excluded by the district court for failure to previously
disclose expert opinions under Federal Rule of Civil Procedure 26.
[Id.]{.underline} at 32-33. Finding that this was the only evidence
Linear provided in opposition to summary judgment, [id.]{.underline} at
33, the district court granted summary judgment of non-infringement in
favor of Maxim, finding that Linear could not prevail on its indirect
infringement claims because it had not established that Maxim's parts
were used to actually prevent reverse average inductor current,
[id.]{.underline} at 34.

Linear argues that the district court erred in granting summary judgment
that Maxim had not contributed to or induced its customers' infringement
of claim 51, by ignoring record evidence indicating Maxim's indirect
infringement. Linear points to Maxim's parts data sheets, items on
Maxim's webpage, an article published in a leading industry journal by
Maxim, and an opinion by Maxim's counsel to argue it presented evidence
that Maxim's customers used the current reversal feature of Maxim's
accused parts.

Maxim responds that summary judgment was properly granted because
Maxim's products do not prevent the reversal of the average inductor
current, as required by the district court's construction of claim 51.
Maxim states that its products are not designed or intended for uses
where average inductor current reversal is possible. It argues that the
Maxim documents to which Linear cites at most address preventing
instantaneous inductor current reversal. Maxim thus contends that Linear
failed in its burden to establish Maxim's contributory infringement or
inducement of claim 51.

Summary judgment is appropriate "if the pleadings, depositions, answers
to interrogatories, and admissions on file, together with the
affidavits, if any, show that there is no genuine issue as to any
material fact and that the moving party is entitled to a judgment as a
matter of law." Fed. R. Civ. P. 56(c). Because Linear bears the burden
of establishing infringement at trial, in moving for summary judgment
Maxim need only establish a deficiency concerning an element of Linear's
infringement claim. [Celotex Corp. v. Catrett]{.underline}, 477 U.S.
317, 322 (1986) ("\[T\]he plain language of Rule 56(c) mandates the
entry of summary judgment, after adequate time for discovery and upon
motion, against a party who fails to make a showing sufficient to
establish the existence of an element essential to that party's case,
and on which that party will bear the burden of proof at trial."). To
survive Maxim's motion for summary judgment of no contributory
infringement or inducement, Linear, as the non-moving party, must
"designate specific facts showing that there is a genuine issue for
trial." [Id.]{.underline} at 324 (internal quotation marks omitted).

Although not directly infringing, a party may still be liable for
inducement or contributory infringement of a method claim under 35
U.S.C. §§ 271(b), (c) if it sells infringing devices to customers who
use them in a way that directly infringes the method claim. [R.F. Del.,
Inc. v. Pac. Keystone Techs., Inc.]{.underline}, 326 F.3d 1255, 1267
(Fed. Cir. 2003). "Liability for either active inducement of
infringement or for contributory infringement is dependent upon the
existence of direct infringement." [Joy Techs., Inc. v. Flakt,
Inc.]{.underline}, 6 F.3d 770, 774 (Fed. Cir. 1993). There can be no
inducement or contributory infringement without an underlying act of
direct infringement. [Id.]{.underline}

While the evidentiary showing in this case may be sparse and not
altogether clear, we believe that Linear has satisfied its burden under
[Celotex]{.underline} by presenting specific facts showing that there is
a genuine issue for trial as to Maxim's contributory infringement or
inducement of claim 51 of the '178 patent. [See]{.underline}
[Celotex]{.underline}, 477 U.S. at 325. Linear's evidence establishes
that Maxim products used at least in IBM computers may have circuitry
that prevents reversal of inductor current. For example, Linear cites a
document from Maxim's webpage that states in pertinent part:

> [Another MAX782 innovation---fast, precise current sensing---allows
> the device to turn off its synchronous-rectifier switch as the
> inductor's discharge current passes through zero.]{.underline} . . .
> Competitive chips either disable the synchronous rectifier completely
> at light loads, or leave it on and pay a big penalty in quiescent
> supply current. ([With the rectifier on, the reversal of inductor
> current after discharge causes a transfer of energy from the output
> capacity back to the battery.]{.underline} . . .)

Appellant's Br. at 53 (quoting Joint Appx. at 14167) (emphases added).
This document raises a factual issue whether Maxim's accused device
turns the switching transistors off to prevent the current to the load
from reversing polarity, as required by claim 51. Even if Linear's
evidence only pertains to instantaneous inductor current, as Maxim
contends, Linear persuasively argues that the "preventi\[on\] \[of\]
instantaneous inductor current also prevents reversal of average
inductor current." Appellant's Reply Br. at 24. In effect, Linear argues
the prevention of instantaneous inductor current by definition prevents
the average inductor current from reversing polarity. This may provide a
basis for establishing that Maxim's devices can directly infringe the
current reversal prevention claims of the '178 patent.

Linear also presented evidence that Maxim's customers directly infringe
by using Maxim's parts to prevent current reversal. Disregarding the
content of Blauschild's "RB I" expert declaration, which was excluded by
the district court, the record nonetheless contains circumstantial
evidence of direct infringement. For example, the record includes a
letter from Maxim's customer, IBM, stating that: "the Thinkpads which
use Maxim chips use the reverse current protection feature of those
chips." Joint Appx. at 11226. This evidence, together with the Maxim
webpage noted above, and other record evidence, provides sufficient
support for Linear to survive summary judgment.

Because Linear's evidence raises a genuine issue as to Maxim's
contributory infringement or inducement of claim 51 of the '178 patent,
we vacate the district court's summary judgment of non-infringement.

C. Cross-Appeal

1\. Inventorship

The parties dispute whether the district court correctly found that
Ronald Vinsant's claim of joint inventorship of the '178 patent was not
corroborated. Maxim argues that Vinsant developed the polarity reversing
circuitry in 1989 while working at Teledyne and that after joining
Linear, Vinsant shared his knowledge with the named inventor Wilcox.
Maxim contends that Vinsant qualifies as a joint inventor and that Maxim
cannot infringe because it has since purchased Teledyne's ownership
interest. Maxim argues that Vinsant provided detailed "written and oral
testimony" that he conceived the claimed polarity reversal prevention
aspects and that the district court erred in finding no corroboration.
Linear responds that the district court did not err because Vinsant
failed to present a single contemporaneous document or witness from
Teledyne to corroborate Vinsant's claim.

The district court found that Maxim failed to present contemporaneous
corroborating documentation or witnesses describing Vinsant's conception
at Teledyne. [See]{.underline} [Summary Judgment Order]{.underline},
slip op. at 62-63 ("Where are the diagrams, notes and letters that
undoubtedly would have been produced contemporaneous with Vinsant's
conception?"). The district court noted that Maxim's evidence was
circumstantial and was "highly ambiguous" and "tangential at best."
[Id.]{.underline} at 62.

A party seeking correction of inventorship must provide clear and
convincing evidence of inventorship. [Hess]{.underline}, 106 F.3d at
979-80; [Ethicon, Inc. v. U.S. Surgical Corp.]{.underline}, 135 F.3d
1456, 1461 (Fed. Cir. 1998). To meet the clear and convincing
evidentiary burden, the alleged co-inventors must prove their
contribution to the conception with more than their own testimony
concerning the relevant facts. [Trovan, Ltd. v. Sokymat SA]{.underline},
299 F.3d 1292, 1302 (Fed. Cir. 2002) (citing [Price v.
Symsek]{.underline}, 988 F.2d 1187, 1194 (Fed. Cir. 1993)). Whether the
co-inventor's testimony has been sufficiently corroborated is evaluated
under a "rule of reason analysis," which requires that an "evaluation of
[all]{.underline} pertinent evidence must be made so that a sound
determination of the credibility of the inventor's story may be
reached." [Price]{.underline}, 988 F.2d at 1195. Corroborating evidence
may take many forms. Reliable evidence of corroboration preferably comes
in the form of records made contemporaneously with the inventive
process. [Sandt Tech., Inc. v. Rosco Metal & Plastics
Corp.]{.underline}, 264 F.3d 1344, 1350-51 (Fed. Cir. 2001).
Circumstantial evidence of an independent nature may also corroborate.
[Trovan]{.underline}, 299 F.3d at 1303. Additionally, oral testimony
from someone other than the alleged inventor may corroborate.
[Id.]{.underline} Maxim cross appeals from the district court's grant of
Linear's motion for summary judgment that Vinsant was not an inventor of
the '178 patent. Summary judgment is properly granted if the evidence,
when viewed in a light most favorable to the non-moving party, fails to
establish the inventorship of an omitted inventor by clear and
convincing evidence. [See]{.underline} [Teleflex]{.underline}, 299 F.3d
at 1323.

In making its inventorship determination, the district court correctly
set forth our inventorship precedent, including the need to evaluate the
evidence of corroboration under a rule of reason analysis.
[See]{.underline} [Summary Judgment Order]{.underline}, slip op. at
55-56. The court then thoroughly reviewed the evidence presented and
concluded that no reasonable juror could find that Maxim had
corroborated Vinsant's testimony that he invented the polarity reversing
circuitry while at Teledyne. [Id.]{.underline} at 63.

a\. Reni Testimony and Exhibit D-136

Maxim presented testimony by Daniele Reni, an Apple employee who
allegedly discussed regulator circuitry with Vinsant while he was at
Teledyne. Maxim also relied on a circuit diagram from Reni's files, made
by Vinsant and referred to at trial as D‑136. [Summary Judgment
Order]{.underline}, slip op. at 57-58. It was undisputed that the D‑136
diagram did not depict a complete synchronous switching regulator. From
the partial circuitry shown in the D‑136 diagram, the district court
could not determine whether the transistor turns off at peak current or
when the current approaches or crosses zero. [Id.]{.underline} at 57.
The district court observed that Reni's testimony did not shed light on
what concepts were depicted in the D-136 diagram. [Id.]{.underline} at
57-58. At best, the district court noted, Reni recalled that he
discussed current reversal with Vinsant and they conducted brainstorming
sessions about this issue. [Id.]{.underline} at 58-59. The district
court observed that it was unclear whether the current reversal to which
Reni testified was "current reversal" within the meaning of the '178
patent claims. [Id.]{.underline} at 59. Noting that Reni's testimony was
at best "terse and cryptic," the court concluded that the testimony and
D-136 diagram did almost nothing to corroborate Vinsant's claim of
inventorship. [Id.]{.underline}

Maxim argues that Reni's testimony and the D‑136 diagram together
corroborate Vinsant's inventorship claim. Maxim contends that whether
the circuit in the D‑136 diagram turned off at peak or near-zero current
was a fact dispute to be resolved by a jury. Further, Maxim argues that
Reni's testimony about "current reversal" described the concept claimed
in the '178 patent.

After reviewing the district court's analysis, we find no error in the
district court's reasoning or conclusion. The district court correctly
observed that Maxim failed to establish that either the circuitry
depicted in the D‑136 diagram or the current reversal concepts Reni
testified that he discussed with Vinsant depicted or explained "current
reversal" within the meaning of the '178 patent claims. At best, Maxim
urges us to re-weigh Reni's testimony and the D‑136 diagram to infer
that they represent details sufficient to corroborate Vinsant's
inventorship claim. Maxim thus fails to establish a dispute of material
fact that either Reni's testimony or the D‑136 diagram corroborated
Vinsant's inventorship of a regulator within the scope of the '178
patent claims.

b\. Notebook Diagram

Maxim also introduced a diagram in a Linear lab notebook labeled "Ron
Vinsant's Laptop Switcher Proposal" dated February 21, 1991 ("notebook
diagram"). [Summary Judgment Order]{.underline}, slip op. at 59-60. The
district court concluded that, even assuming the notebook diagram
depicted a circuit within the scope of the '178 patent claims, the
notebook diagram would still fail to corroborate Vinsant's claim that he
conceived of current reversal circuitry at Teledyne. [Id.]{.underline}
at 60. The court noted that at best, the notebook diagram could only
establish Vinsant's conception at Linear, [id.]{.underline}, after he
left the employ of Teledyne. Maxim argues that the notebook diagram
"lends great credibility" to Vinsant's testimony that he explained
approaches he had previously used at Teledyne to the named inventor
Wilcox at Linear. Cross-Appellant's Br. at 65.

The district court's conclusion was based on sound facts and analysis.
The notebook diagram is inconclusive of what circuitry Vinsant may have
developed while at Teledyne, and thus fails to corroborate Vinsant's
claim. The notebook diagram only documents the current reversal
circuitry Vinsant discussed at Linear, and not what circuitry Vinsant
may have previously developed at Teledyne. Again, Maxim fails to
establish an error in the district court's conclusion that the notebook
diagram could only corroborate Vinsant's alleged conception at Linear.

c\. Vinsant's Drawing for Counsel

Maxim presented to the district court a circuit diagram Vinsant produced
in 1998 when he met with Maxim's counsel. [Summary Judgment
Order]{.underline}, slip op. at 57. The district court did not
explicitly analyze this evidence in its opinion.

Maxim argues that a circuit diagram Vinsant produced when he met with
Maxim's counsel contains elements of the current reversal claims, even
though Vinsant never reviewed the '178 patent. Maxim argues that because
this drawing is simply a "more detailed version" of the contemporaneous
D-136 and notebook diagrams, it supports Vinsant's account.
Cross-Appellant's Br. at 65-66. Linear responds that this drawing was
litigation-inspired, Vinsant was shown the '178 patent by defense
counsel, and Vinsant had heard defense counsel's characterizations of
the patent.

We have previously held that the most reliable corroborating evidence
are "records made contemporaneously with the inventive process." [Sandt
Tech.]{.underline}, 264 F.3d at 1350-51. Because this record was made in
1998, many years after Vinsant allegedly conceived of the current
reversal circuitry at Teledyne, it is of questionable value as
corroboration for Vinsant's claim of conception during his employment at
Teledyne. We find no error in the district court's failure to discuss
this diagram.

Because the district court, after viewing the evidence in a light
favorable to Maxim, correctly concluded that no reasonable juror could
find that Vinsant's inventorship claim was corroborated, we affirm the
district court's grant of summary judgment that Vinsant was not an
inventor of the '178 patent.

III\. CONCLUSION

Because the district court erred in construing the "circuit," "vary the
duty cycle," and "simultaneously off" claim limitations of the '178
patent, we vacate the judgment of non-infringement and remand for
further consideration. We further vacate the district court's summary
judgment of no contributory infringement or inducement of the current
reversal method claims of the '178 patent, because genuine issues of
material fact have been raised concerning Maxim's contributory
infringement or inducement. As to Maxim's cross-appeal, because the
district court did not err in granting summary judgment that Vinsant was
not a joint inventor of the '178 patent, we affirm.

[VACATED-IN-PART, AFFIRMED-IN-PART, AND REMANDED]{.underline}.

IV\. COSTS

No costs.