Source: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-cand-3_94-cv-01633/USCOURTS-cand-3_94-cv-01633-0/pdf.json

Nature of Suit Code: 830
Nature of Suit: Patent
Cause of Action: 28:1338 Patent Infringement

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United States District Court

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United States District Court

For the Northern District of California

UNITED STATES DISTRICT COURT

NORTHERN DISTRICT OF CALIFORNIA

LINEAR TECHNOLOGY CORP.,

Plaintiff,

 vs.

MICREL, INC.

Defendant. /

No. C-94-1633 MHP

FINDINGS OF FACT AND

CONCLUSIONS OF LAW

On May 9, 1994, plaintiff Linear Technology Corp. (“LTC” or “Linear”) brought this action

against defendant Micrel, Inc. (“Micrel”) alleging infringement of United States Patent Number

4,755,741 (hereinafter the “‘741 patent”) and the accompanying reexamination certificates. 

BACKGROUND

On July 5, 1988 the ‘741 patent pertaining to adaptive transistor drive circuitry was issued. 

The asserted claims in this action are claims 22, 32, 36–44, 46, 47 and 49. The ‘741 Patent covers

an adaptive transistor drive circuit for use in electrical devices where a transistor is used “as a switch

in a switching voltage regulator.” ‘741 patent, col. 1, l. 17. The claimed inventive improvements in

the ‘741 patent include the ability of the drive circuit to operate across a range of collector currents

and temperatures and to operate with high electrical efficiency. Id. at col. 2, ll. 43–66. 

On May 14, 1991, the B1 Reexamination Certificate for the ‘741 Patent (“B1 Certificate”)

issued, following a reexamination of the ‘741 Patent (“Reexam I”). On April 28, 1994 an

anonymous third party requested reexamination of the ‘741 patent (“Reexam II”). 

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LTC sent a notice of possible infringement referencing the ‘741 Patent to Micrel on April 3,

1993, and on May 9, 1994 LTC filed suit against Micrel alleging infringement of the ‘741 Patent and

the B1 Certificate. Defendant Micrel requested reexamination of the amended ‘741 Patent on

September 9, 1994 (“Reexam III”). Reexam II and Reexam III were merged in January 1995, and

on December 26, 1995 the B2 Reexamination Certificate (“B2 Certificate”) issued.

 In the same year that the lawsuit and Reexam III commenced, Micrel began selling the

MIC2171, MIC2172, and MIC32172 circuits (the “Accused Products”). Before the December 26,

1995 issue of the B2 Certificate Micrel had already shipped 279,655 units of those products. Micrel

later changed the design of its devices to eliminate the circuitry which formed the basis of LTC’s

infringement contentions. 

This action was initially assigned to United States District Court Judge Eugene F. Lynch. On

February 26, 1997, Judge Lynch denied Micrel’s motion for summary judgment on the question of

the validity of the ‘741 patent, identifying a genuine issue of material fact regarding the applicability

of the on-sale bar provision of 35 U.S.C. section 102. In the same order, Judge Lynch bifurcated this

action, permitting the on-sale bar issue to proceed to trial while staying all other issues. 

Approximately six months later, the case was reassigned to this court, and the court

subsequently conducted a bench trial on the issue of on-sale bar invalidity. On August 19, 1999 this

court found the ‘741 patent invalid under section 102(b), entering judgment for Micrel accordingly. 

On appeal, the Federal Circuit affirmed this court’s decision in part, reversed in part, and remanded. 

See Linear Tech. Corp. v. Micrel, Inc., 275 F.3d 1040 (Fed. Cir. 2002), cert denied, 538 U.S. 1052

(2003). The Federal Circuit subsequently denied a petition filed by Micrel for a rehearing of the

appeal. On July 3, 2002, Micrel petitioned the United States Supreme Court for a writ of certiorari

to review the judgment of the Federal Circuit. The Supreme Court denied this petition on May 19,

2003. 

On January 24, 2004 this court conducted a limited claim construction for the ‘741 Patent

and accompanying certificates, construing the word “saturation” to mean “the state in which the

ratio of collector-current to base-current is forced lower by excess base current” and the phrase “in

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saturation” to mean “the working of the covered invention consistently at a state of forced current

gain.” Memorandum & Order, No. C 94-1633 MHP, slip op. at 12, 17 (Jan. 22, 2004).

On November 11, 2005, the court granted in part and denied in part defendant’s motion for

summary judgment. The court held that (1) the B1 Certificate is invalid for indefiniteness, (2)

defendant Micrel is entitled to the defense of absolute intervening rights for the 279,655 units of

Accused Products shipped before the issuance of the B2 Certificate on December 26, 1995, (3)

defendant was not entitled to summary judgment regarding the alleged 307,135 in inventory as of

December 26, 1995, (4) Micrel is entitled to summary judgment that the $500,000 it spent in

developing the Accused Products prior to the B2 Certificate’s issuance is “substantial preparation”

under 35 U.S.C. section 252 and (5) products incorporating defendant’s change in design do not

infringe any asserted claim. 

The court conducted a bench trial of the remaining issues in November of 2005. The issues

before the District Court at this time are (1) whether the ‘741 patent is enforceable; (2) whether

Micrel has infringed claims 22, 32, 36–44, 46–47 and 49 of the ‘741 patent; (3) if infringement is

found, what amount of compensation LTC would be entitled to receive for the damages that

resulted; (4) whether Micrel’s alleged infringement was willful, such that the damages awarded

should be increased; (5) whether because of its change in design and/or because of intervening rights

Micrel is entitled to a limitation on its damages, and (6) whether this case is exceptional and attorney

fees should be awarded. 

Having considered the testimony presented at trial and the other evidence submitted by the

parties, the court FINDS for plaintiff Linear and enters the following findings of fact and

conclusions of law in accordance with its obligations under Federal Rule of Civil Procedure 52(c). 

Fed. R. Civ. P. 52(c) (requiring judgment under Rule 52(c) to be supported by findings of fact and

conclusions of law). 

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TABLE OF CONTENTS

Findings of Fact

I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

II. Unenforceability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

A. Commercial Activity prior to November 18, 1985 . . . . . . . . . . . . . . . . . . . . . . . . . 7

1. Individual Charged with Inequitable Conduct . . . . . . . . . . . . . . . . . . . . . . .7

2. Information that was not disclosed to the PTO . . . . . . . . . . . . . . . . . . . . 14

B. Non Disclosure of SG1524, LM111 and LM119 . . . . . . . . . . . . . . . . . . . . . . . . . 18

1. Individuals Charged with Inequitable Conduct . . . . . . . . . . . . . . . . . . . . 18

2. Prior Art Considered by the PTO During Prosecution . . . . . . . . . . . . . . . 19

3. Other Prior Art disclosed by LTC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4. Knowledge and Relevance of the SG1524, the LM119 

and the LM111. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 

III. Infringement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

A. The Invention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

B. Saturation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

C. Micrel’s Accused Products Infringe the ‘741 Patent . . . . . . . . . . . . . . . . . . . . . . 45

D. Micrel’s Testing of a 1990 SG1524 is Irrelevant to an

Infringement Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

IV. Damages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54

A. Intervening Rights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54

B. Implementation of the 1998 Design-Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

C. Period of Infringement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

D. Lost Profits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

1. Demand for Patented Feature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

2. Absence of Acceptable Non-Infringing Alternatives . . . . . . . . . . . . . . . . 72

(a). Process of Choosing a Switching Regulator . . . . . . . . . . . . . . . . .72

(b). Micrel’s Non-Infringing Alternative . . . . . . . . . . . . . . . . . . . . . . .75

(c). Third-Party Non-Infringing Alternatives . . . . . . . . . . . . . . . . . . . 78

3. LTC’s Manufacturing Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

4. LTC’s Market Share . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92

(a). Unreliability of Dragun’s Market Share Analysis . . . . . . . . . . . . 92

(b). Third Party Estimations of LTC’s Market Share . . . . . . . . . . . . 101

5. Amount of Lost Profits to be Awarded . . . . . . . . . . . . . . . . . . . . . . . . . .101

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(a). Lost Sales from Design-In Wins . . . . . . . . . . . . . . . . . . . . . . . . . 102

(b). Price Erosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

6. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

E. Reasonable Royalty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

V. Willful Infringement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

A. Pre-1994 — Design and Fabrication of the Accused Products . . . . . . . . . . . . . . 113

1. Micrel’s Copying Efforts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

2. Concealment of Infringement Activities . . . . . . . . . . . . . . . . . . . . . . . . . 121

B. 1994 Onwards — Good Faith Belief in Invalidity/Unenforceability/

Intervening Rights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127

VI. Damages Award . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

Conclusions of Law

VII. Unenforceability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

A. Materiality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

B. Intent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 

C. Undisclosed Commercial Activity Prior to November 18, 1985 . . . . . . . . . . . . . 136

D. Non-Disclosure of SG1524, LM119 and LM111 . . . . . . . . . . . . . . . . . . . . . . . . .143

VIII. Infringement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

IX. Damages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

A. Intervening Rights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

B. Implementation of the 1998 Design-Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

C. Lost Profits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151

1. Demand for the Patented Feature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

2. Absence of Non-Infringing Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . 156

3. LTC’s Market Share . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .159 

(a). Admissibility of Dragun’s Expert Testimony . . . . . . . . . . . . . . . 165 

4. Amount of Lost Profits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .166

D. Reasonable Royalty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

X. Enhanced Damages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

A. Willful Infringement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .164

B. Attorneys’ Fees & Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169

XI. Prejudgment Interest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

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FINDINGS OF FACT1

I. INTRODUCTION

1. Plaintiff LTC is a corporation organized and existing under the laws of the State of

California and having a principal place of business in Milpitas, California. Initial Findings of Fact

(hereinafter, “IFF”) ¶ 1; Def’s Exh. A-229.

2. Defendant Micrel is a corporation organized and existing under the laws of the State of

California having its principal place of business in San Jose, California. IFF ¶ 2; Def’s Exh. A-229.

3. The patent at issue in this case is the ‘741 patent,” entitled “Adaptive Transistor Drive

Circuit,” as amended by the B1 and B2 Certificates. The named inventor is Carl Nelson and LTC is

the assignee of all right, title and interest in the ‘741 patent. Def.’s Exh. A-33; Nelson Testimony,

192:25–193:1.

4. The ‘741 patent discloses an “adaptive transistor drive circuit.” Def.’s Exh. A-33 at 1:5–21. 

The adaptive transistor drive circuit disclosed in the ‘741 patent describes “switching regulator

circuitry” used to provide regulated voltages or currents. Nelson Testimony, 143:1–2.

5. The LT1070 chip manufactured by LTC is a switching voltage regulator invented by Nelson

and embodies an aspect of every claim contained in the ‘741 patent, except for claims 2 and 12. 

Nelson Testimony, 139:20–141:18; 199:20–200:17. However, the LT1070 switching regulator

circuit embodies the inventions claimed in all of the claims of the ‘741 patent that LTC asserts are

infringed by Micrel. Joint Pretrial Conference Statement filed November 14, 2004 (Docket Entry

No. 335) (hereinafter “Jt. Pretrial Conf. Stmt.”) at ¶ 7. The LT1070 silicon chip initially constructed

and tested by Nelson was essentially a functioning version of the ‘741 patent. Nelson Testimony, at

142:18–25; ‘741 patent, Pl.’s Exh. 220 at LIN018411, 416–17. 

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6. On November 18, 1986, LTC filed a patent application on an adaptive transistor drive circuit,

which led to the issuance of the ‘741 patent. IFF 5; Nelson Testimony, 182:8-24, 190:8-16; Pl.’s

Exhs. 1, 120.

7. LTC’s LT1070 switching voltage regulator, the first integrated circuit in the family of

regulators that includes the LT1171 and LT1172, was introduced in December of 1985. Dobkin

Testimony, 22:8–16; Def.’s Exh. A. The LT1070 and its progeny were a success, especially with

manufacturers of battery-powered, portable electronic devices. Nelson Testimony, 156:1-157:6.

8. LTC soon followed the LT1070 with numerous other switching voltage regulators including

the adaptive base drive invention covered by the ‘741 patent, including the LT1071, LT1072,

LT1170, LT1171, and LT1172. Dobkin Testimony, 24:5-25:10; Nelson Testimony, 154:4-17,

203:4-204:19; Blauschild Testimony, 366:11–367:20, 377:6–9.

9. LTC seeks damages for the alleged infringement of the LT1171 and the LT1172 (the

“Patented Products”). Jt. Pretrial Conf. Stmt. at 3:19. 

II. UNENFORCEABILITY

10. Micrel asserts that Robert Scott, Carl Nelson and Robert Dobkin engaged in inequitable

conduct in the prosecution of the ‘741 patent.

A. Commercial Activity prior to November 18, 1985

1. Individual Charged With Inequitable Conduct - Robert Scott

11. Robert Scott is an employee of LTC. During the prosecution of the ‘741 patent he was a

Product Marketing Manager at LTC. Scott Testimony, 260:3–5; 261: 3–5.

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12. On July 31, 1987 Scott submitted a declaration to the PTO addressing some of the issues

raised by the on-sale bar. Pl.’s Exh. 120 at LIN 000186–87 (hereinafter Def.’s Exh. A-19). This

declaration was submitted with LTC’s Information Disclosure statement to the PTO. In preparing

for his declaration, Scott conducted, at the direction of LTC management, an investigation of all

sales and advertising activity for the LT1070 before November 18, 1985—the critical date. Scott

Testimony, 277:23–288:21; 264:24–265:5. All information that Scott found, or of which he was

aware, was disclosed in his declaration to the PTO. Id. at 265:1–11; 287:23–288:21; Def.’s Exh. A-

 19.

13. In his declaration, Scott discussed inter alia: his oral communications with LTC’s

independent sales representatives and distributors concerning the LT1070 [Def.’s Exh. A-19 ¶ 3];

LTC’s July 1985 sales training meeting [Id., ¶¶ 4–7]; two meetings that Dobkin, vice-president of

LTC, had with customers at which reference was made to the LT1070 [Id., ¶ 8]; LTC’s receipt of

sample orders for the LT1070 [Id., ¶¶ 9–10]; Scott’s recollection of a telex order for the LT1070

received from Jermyn, S.A. [Id., ¶ 11]; his November 6, 1985 telex to LTC’s area sales managers,

alerting them to the fact that LTC had received requests for samples and production orders for the

LT1070 on or before November 6, 1985 [Id., ¶¶ 13–15; Scott Testimony, 272:17–273:8]; LTC’s

November 1, 1985 Newsline discussing the LT1070 [Def.’s Exh. A-19 ¶ 12]; an article, published in

the Electronic Design magazine about the LT1070 and a subsequent LTC Newsline article [Id., ¶¶

19–20]; and the LTC Released Product Listing form for the LT1070. Id., ¶ 16.

14. Although Scott disclosed the receipt of pre-critical date orders for the LT1070 to the PTO, he

did not disclose the use that LTC made of those orders by putting them in the “will advise” category. 

Thus, neither LTC’s Information Disclosure Statement concerning on-sale bar issues nor the

accompanying LTC declarations (including Scott’s declaration) disclosed that customers Microlog,

Neye, Bacher, and Svensk all placed orders for LT1070s prior to the critical date, that LTC did not

reject these orders but instead carried them on its books under the “will advise” rubric, and that LTC

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converted these orders into LT1070 orders shortly after the critical date and then shipped the

products to the customers without any further action on the part of the customers. Compare LTC’s

Information Disclosure Statement, Exh. 120 at LIN 00070-255, with IFF ¶¶ 83–96. See also IFF ¶

92; Scott Testimony, 293:14–21. 

15. With respect to the requests for samples and product orders, Scott characterized them as

“typically unsolicited requests made by LTC’s independent sales representatives and distributors.” 

Def.’s Exh. A-19 ¶ 11. According to Scott the “unsolicited requests and orders” received before the

critical date were ignored: “On information and belief, however, no LT1070 devices were offered

for sale or shipped by LTC prior to November 18, 1985.” Def.’s Exh. A-19 ¶ 14.

(a). 1994 Document Discoveries

16. In January of 1994 Scott asked Daniel Wark, who was at that time serving as LTC’s Manager

of Production Control and Customer Service, to search for sales orders, sales and activity reports

from 1984–1986. Wark searched for these materials in a remote LTC warehouse located a few miles

from the LTC headquarters and discovered a sales order report for the relevant period of time. Wark

gave this report to Scott, who noticed that a number of entries were for the LT1070s and were

associated with sales orders that predated the critical date. Wark Testimony, 395:20–396–25;

393:4–5; Def.’s Exh. A-571 ¶ 8.

17. Consequently, in February 1994, both Scott and Wark returned to the warehouse to search

for any further information relating to the LT1070. Scott Testimony, 277:8–25, 304:1–4,

304:24–305:2; Wark Testimony, 396:10–16; Def.’s Exh. A-571 ¶ 15. 

18. The warehouse comprised a massive open storage area containing myriad objects—old

electronics equipment, cars, two levels of pallets of boxes of documents, and no index specifying the

contents of the boxes. After determining where the Linear Technology section of the warehouse was

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located, Scott and Wark opened and searched through the boxes there for other information

concerning the LT1070. Scott Testimony, 277:11–21, Wark Testimony, 396:22–397:13. 

19. During this February 1994 search, Scott and Wark located approximately three additional

bound computer printouts which contained information related to the LT1070 for the relevant time

period. Scott Testimony, 277:22–25, 278:7–10, 304:1–7, 304:24–305:2; Wark Testimony,

396:10–16, 402:24–403:1; Def.’s Exh. A-571 ¶ 15.

20. When Scott determined that the additional bound computer printouts contained pre-critical

date LT1070 customer order information, he gave all the printouts to LTC’s attorneys and suggested

to Wark that he should prepare a declaration discussing the discoveries. Scott Testimony,

277:22–278:2, 305:3–9, 306:19–25; Wark Testimony, 397:17–23; Rowland Testimony, 955:18–23,

956:13–18.

21. In June of 1994, Wark filed a declaration with the PTO during Reexam II. Scott Testimony,

277:1–278:4; Exh. A-571; Wark Testimony, 395:7–16; Rowland Testimony, 951:24–963:23. 

22. Wark and Scott were not aware of the existence of the bound computer printouts prior to

1994. Scott Testimony, 274:2–6; Wark Testimony, 397:14–16.

23. The focus of Scott’s search in 1994 was not on the “will-advise” notations found on some of

the computer printout pages and thus he did not investigate the relevance of these notations. Scott’s

focus in 1994 was on the fact that the bound computer printouts contained LT1070 entries from the

November 1985 time period. Scott Testimony, 274:25–275:10, 302:18–303:16, 305:3–9.

24. The Wark declaration provided excerpts from LTC’s Sales Order Reports and Bookings by

Customer Reports (“Booking reports”), which contained line items showing “will advise” entries. 

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Without knowing more about the “will-advise” procedure, it was not possible to understand that

these entries were made in connection with orders for the LT1070 prior to the critical date. 

25. The Wark declaration did not disclose that the “will advise” procedure had been used in

connection with the LT1070, or discuss it in any way. See Def.’s Exh. A-571; compare id. at

LIN00871–84 with IFF ¶ 92. 

26. At the time he reviewed the documents, Wark did not know that the “will-advise” notations

were significant and thus he had no reason to ask Scott what the entries meant. Wark Testimony,

403:2–8. 

(b). Will-Advise Notations

27. During his initial deposition on August 14, 1996, Scott was asked whether he knew what the

“will-advise means under the product number column on the report” containing entries for LT1070s. 

Scott responded that he “did not know what ‘will-advise’ meant. See Scott Testimony, 308:11–16.

 

28. During his subsequent deposition on April 3, 1997, Scott testified that during 1987 he was

aware of the “will-advise” designation “as a very general term to flag defects in requests and orders

that came in.” Scott Testimony, 297:3–6. However, at trial, Scott testified that he was unaware

when he signed his declaration to the PTO in 1987 that any orders for the LT1070 had been

designated as “will-advise” entries in LTC’s booking system. Scott Testimony, 295:15–24. 

29. Micrel’s reliance upon this deposition testimony to impeach Scott is unpersuasive. Scott

initially testified that he was not aware of what will-advise meant in one particular instance—the

meaning of the will-advise notations entered in the column next to the LT1070 pre-critical date

orders. Later during the on-sale bar trial, Scott testified that he had a general awareness of the term. 

Scott’s prior testimony is not inconsistent with his trial testimony since a general understanding of

the use of the term does not suggest an understanding of its use with respect to the LT1070 orders. 

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30. Serena Lucey was working as a customer service representative during the period of the

initial prosecution. Lucey Dep. at 7:3–8. At her deposition, Lucey testified that after receiving a

telex from a foreign distributor requesting a product that had not yet been released, the customer

service department would contact the marketing department to verify if the product had been

released. At that time, the marketing department comprised Scott and a “couple more people.” 

Scott Testimony, 260:10–18. If the product had not been released, then a “will-advise” category

would be used. Lucey Dep. at 37:6–38:25. 

31. During the initial trial on the on-sale bar issue, Lucey testified that Scott was not necessarily

aware of the will-advise procedure. According to Lucey, his familiarity lay with whether the

product had been officially released. Lucey Testimony (1998 Trial), 578:14–23.

32. Scott testified that he asked individuals in customer service whether any of the orders

referenced in his telex had been entered with the notation “will-advise.” Scott did not receive a

response from customer service and did not follow up with the department. Scott Testimony,

296:16–297:7. 

33. Scott testified that it would have been not simply important, but “vital,” for the PTO to have

known that the orders referred to in his 1987 declaration had been entered into LTC’s records as

“will advise” orders. Scott Testimony, 295:12–19. 

34. Mark Rowland, one of the prosecuting attorneys in the prosecution which resulted in the

issuance of the ‘741 patent, testified that if he had known that production orders were entered into

the LTC bookings system as “will advise” entries, he would have considered that fact to be

information that should have been disclosed to the PTO. Rowland Testimony, 932:15–17,

943:10–24 (emphasis added). 

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35. LTC concedes that the patent examiner was totally dependent on what LTC provided him

regarding LTC’s internal documents and had no way of understanding that the LT1070 orders were

originally handled as “will advise” transactions prior to the critical date. Rowland Testimony,

939:15–940:13.

(c). Manual of Patent Examination Procedure

36. Rowland testified that he was familiar with the PTO’s Manual of Patent

Examination Procedure (“MPEP”) and that he sometimes used it as a reference resource in

patent prosecution. Rowland, 935:11–13. 

37. The MPEP states in its foreword that its aim is to provide “patent examiners,

applicants, attorneys, agents and representatives. . . a reference work on the practices and

procedures . . . [incident] to the prosecution.” In the edition in effect at the time of the

prosecution of the ‘741 patent, under the heading “Significant Factors Indicative of

Commercial Exploitation,” the MPEP notes that the following activities “should be used by

the examiner as indicia of . . . subjective intent” to engage in “premature commercial

exploitation” of a “completed invention”: 

• Preparation of various contemporaneous “commercial documents,” e.g.,

orders, invoices, receipts, delivery schedules; 

• Preparation of price lists;

• Display of samples to prospective customers;

• Demonstration of models or prototypes;

• Use of an invention where an admission fee is charged;

• Advertising in publicity releases, brochures and various periodicals.

See MPEP § 2125.03 (8th Ed., Oct. 1986 Rev.) (hereinafter “Def.’s Exh. A-690”). 

The manual states that “the above activities may be determinative of ‘commercial

exploitation’ even though (1) prices are estimated rather than established, (2) no commercial

production runs have been made, and (3) the invention is never actually sold.” Def.’s Exh.

A- 690 § 2125.03.

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38. Further, the MPEP notes that whether commercial activity is “on-sale” under section

102(b) “depends upon the circumstance of the activity—the basic indicator being the

subjective intent of the inventor.” MPEP § 2133.03(e)(1) (5th Ed., Oct. 1987, Rev.). Thus,

“any [pre-critical date activity is an] attempt at market penetration” which invalidates a

patent. Id. (emphasis added).

2. Information that was not Disclosed to the PTO

(a). Preliminary Data Sheet

39. In his declaration, Scott stated that neither the preliminary data sheet nor the 1986

Data Book was publicly available or distributed by LTC prior to November 19, 1985. 

Def.’s Exh. A-19 ¶ 18.

40. LTC’s Information Disclosure Statement and the attached declarations did not

disclose that the preliminary datasheet for the LT1070 (drafted by the inventor, Carl Nelson)

was distributed to a number of potential customers prior to the critical date by LTC’s sales

representatives. Compare LTC’s Information Disclosure Statement, Exh. 120 at LIN

00070–255 (all declarations), with IFF ¶¶ 28, 42, 43, 45, 48.

41. There is no evidence in the record establishing that Scott was aware before the filing

of his declaration that these distributions of the preliminary datasheet had occurred. 

(b). Discussions of the LT1070 at the July 1985 Sales Meeting

42. Scott disclosed in his declaration filed with the PTO that the LT1070 was discussed

at a sales meeting held on July 21–23, 1985. See Exh. A-19. He stated in his declaration

that the LT1070 presentation at the meeting was “solely to encourage the sales

representatives and distributors to identify and familiarize themselves with potential users of

the [LT1070] product.” Id. at LIN 00186. However, at the first trial he testified that LTC

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 expected its sales representatives and distributors to actually discuss the LT1070 and its

functions with customers and explore possible applications. IFF ¶ 36.

43. Scott did not disclose to the PTO that amongst the attendees at the July meeting were

actual customers for the LT1070, namely its international distributors Microlog, Neye, and

Svensk. These distributors purchased products from LTC and then resold them to their own

customers. These very same customers also submitted orders for the LT1070 prior to the

critical date. Compare Exh. 120 at LIN 00186–87, with IFF ¶¶ 20, 32, and 92.

44. There is no evidence in the record that Scott was aware in 1987 that some of the

attendees at the July sales meeting were potential customers. 

45. LTC’s Information Disclosure Statement and the attached declarations failed to

disclose that the inventor, Nelson, made a presentation about the LT1070 at the meeting in

July of 1985. This presentation included discussion of an application circuit diagram which

demonstrated how the LT1070 could actually be used to those in the audience. Compare

Pl.’s Exh. 120 at LIN 00070–255 with IFF ¶¶ 32–34.

46. Although inventor Nelson was involved in commercial activity before the critical

date, he did not file a declaration with the PTO during the original prosecution of the ‘741

patent. In 1995 during Reexam II, Nelson did file a declaration about the “commercial

success” of the LT1070, but failed to mention his marketing activities for the LT1070 prior

to the critical date. See Exh. 123 at 860–909.

47. At the July 1985 sales training meeting and in discussions with, or presentations to,

customers. Nelson was permitted to discuss only the technical details of LTC products, not

details of his inventions or any sales information. He was not permitted to offer the LT1070

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for sale—“If the word ‘price’ or ‘availability’ came out of my mouth the salesman would

cut me off at the knees.” Nelson Testimony, 201:4-18.

48. There is no evidence in the record that Scott was aware in 1987 that Nelson had

spoken with LTC’s representatives and distributors or to customers about the LT1070

during the July 1985 sales training meeting. 

(c). Contact with Potential Customers

49. LTC’s Information Disclosure Statement and the attached declarations also failed to

disclose the extent of pre-critical date contacts by LTC with potential customers for the

LT1070. Although Scott stated in his declaration that Dobkin had discussed the LT1070

during visits with two LTC customers, see Exh. 120 at LIN 00187, he did not disclose that

Nelson also gave customer presentations on the LT1070 to Data General and IBM prior to

the critical date. See IFF ¶¶ 72–74. Nor did Scott disclose that prior to the critical date

LTC’s sales representatives actively promoted the product to many customers, including

Sperry, Honeywell, and Norand. Compare Pl.’s Exh. 120 at LIN 00070–255, with IFF ¶¶

41–52.

50. There is no evidence in the record that Scott was aware in 1987 of the extent of the

pre-critical date contacts by LTC’s representatives with potential customers. 

(d). Will-Advise Entries

51. LTC’s Information Disclosure Statement and the attached declarations failed to

disclose that as a result of the commercial activity before the critical date, LTC was able to

formally book orders for more than 1,700 LT1070s in the four days immediately following

the critical date. Compare Pl.’s Exh. 120 at LIN 00070–255, with IFF ¶¶ 97–99.

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52. It is undisputed that LTC received orders or “requests” for LT1070s prior to the

critical date. Since the LT1070 was not yet formally released, these requests could not be 

entered into LTC’s order entry system as orders for the LT1070 when they were received. 

Instead, LTC used the phrase “will advise” as an electronic marker or placeholder in LTC’s

order entry system for the requested LT1070s. LTC kept track of these “will advise” orders

in its Orders On Hold report. Once the part number for the LT1070s was entered into

LTC’s computerized bookings system, the “will advise” entry was deleted and the

“requests” were formally booked as “orders” for the product. IFF ¶¶ 83–90.

53. For each of these “will advise” designated transactions, no further communication

from the customer was required for LTC to process and ship the order. LTC simply entered

the order for the LT1070s once the part number had been added to LTC’s computerized

database and, thereafter, shipped the LT1070s to fill the orders. Included in these “will

advise” transactions were orders for 50 LT1070s from Microlog, 50 LT1070s from Neye,

100 LT1070s from Bacher, and 600 LT1070s from Svensk—all received and entered into

the order entry system as “will advise” orders prior to the critical date. IFF ¶¶ 91–95 (citing

Def.’s Exh. A–80).

54. Nevertheless, neither LTC’s Information Disclosure Statement concerning on-sale

bar issues nor the accompanying LTC declarations disclosed that customers Microlog,

Neye, Bacher, and Svensk all placed LT1070 orders prior to the critical date, that LTC did

not reject these orders but instead carried them on its books under the “will advise”

designation, and that LTC converted these orders into LT1070 orders shortly after the

critical date and then shipped them to the customers without any further action on the part of

the customers. Compare Pl.’s Exh. 120 at LIN 00070–255, with IFF ¶¶ 83–96. 

55. The entry of the Neye, Microlog and other LT1070 orders into LTC’s order entry

system as orders with “will advise” notations prior to the critical date was in itself the

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preparation of a “contemporaneous ‘commercial’ document” in electronic form. See Exh.

A-690. The use of the “will advise” designation to enter the LT1070 orders into LTC’s

 bookings system also resulted in acknowledgments of these orders being issued. IFF ¶ 87. 

These order acknowledgments were a second “contemporaneous ‘commercial’ document”

under the MPEP.

56. Although LTC disclosed the sales order reports, they did not disclose the relevance

of the “will-advise” entries.

B. Non-Disclosure of SG1524, LM111 and LM119

1. Individuals Charged With Inequitable Conduct 

(a). Carl Nelson

57. As the named inventor of the ‘741 patent, Nelson was intimately involved the

drafting and prosecution of the ‘741 patent. See ‘741 patent; Pl.’s Exh. 120 at LIN 00060;

Nelson Testimony, 216:24–217:4.

(b). Robert Dobkin

58. Dobkin was one of the founders of LTC in 1981, and has been a vice-president of

the company since that time. Dobkin Testimony, 11:7,14–15. Dobkin was intimately

involved in the drafting and prosecution of the ‘741 patent. During the 1980s, if an engineer

thought his invention was patentable, he would consult with Dobkin, who was at the time

the de facto patent committee at LTC, and together they would make a decision whether to

file a patent application. Dobkin Testimony, 101:13–102:20. 

59. Dobkin authorized the filing of at least three patents on Nelson’s invention,

including the ‘741 patent. Dobkin Testimony, 104:2–25. Dobkin and Nelson exchanged

ideas and decided on which aspects of the invention to file a patent application. Nelson

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Testimony, 215:25–216:4. Additionally, Dobkin was in control of the copies of documents

filed with or received from the PTO regarding prosecution of the ‘741 patent. Dobkin

Testimony, 75:25–76:7; 102:15–20.

60. From occasionally speaking with Mr. Nelson about his progress in designing the

circuit, Dobkin was familiar with the circuitry of Nelson’s invention. Dobkin Testimony,

103:21–104:1. 

2. Prior Art Considered by the PTO During Prosecution

61. During the original prosecution of the ‘741 patent, the PTO examiner rejected some

of the patentee’s claim because of a prior art patent that was issued to Lethellier, U.S. Patent

No. 4,595,974. The Patent Examiner also considered two prior patents: U.S. Patents Nos.

4,654,769 (“Melamed”) and 4,645,945 (“De Sartre”). See Pl.’s Exh. 120 at LIN 00062, LIN

00067. All of these patents claimed devices which operated in saturation. 

(a). Lethellier

62. Lethellier discloses a circuit in which the output transistor operates in saturation. 

The PTO examiner recognized that the Lethellier transistor operated in saturation, stating,

“Lethellier discloses the transistor operated at a chosen point in saturation . . .” Pl.’s Exh.

120 at LIN 00063. 

63. The Lethellier circuit includes a Baker clamp. Nelson Testimony, 191:9–11; Pl.’s

Exh. 453 at col. 1, ll. 60–64; col. 3, ll. 46–62. Baker clamps are a combination of diodes

and circuits that establish differing voltage states at the two nodes. If properly used, a Baker

clamp can keep a device out of saturation. McAlexander Testimony, 663:3–664:7. Nelson

understood that this Baker clamp would work to prevent the transistor from going into

saturation and thus the Lethellier circuit could only operate in saturation at a single

operating point. Nelson Testimony, 191:9–192:17.

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(b). Melamed

64. Melamed also discloses a circuit wherein the switching transistor operates in

saturation. Nelson Testimony, 193:7–18, 194:8–12. Melamed also discloses using a Baker

clamp. Nelson Testimony, 194:8–15; Pl.’s Exh. 452 at col. 1, ll.66–col. 2, ll. 24, col. 3, ll.

31–37.

65. The Melamed circuit was designed to operate the transistor in saturation while

staying near the edge of saturation. Nelson Testimony, 195:21–22; Pl.’s Exh. 452 at col. 1,

ll. 66–col. 2, l. 24.

66. The PTO examiner recognized that the Melamed circuit operated in saturation,

stating, “Melamed [and another reference] both disclose circuits for maintaining transistors

at a certain level of saturation.” Pl.’s Exh. 120 at LIN 00064; see also Nelson Testimony,

194:4–15. 

67. Nelson understood that the Melamed circuit was developed to operate a transistor at

a single operating point because of the types of diodes used by the designer. The designer

had a choice between diodes that had a very low forward drop to keep the transistor out of

saturation and diodes with a high forward voltage which would keep the circuit deep in

saturation. Once the designer of this circuit decided upon the diodes he would use for

production, the circuit’s condition of operation would be fixed since any variance in

temperature or current would move the circuit in and out of the desired saturation condition. 

Nelson Testimony, 195:19–195:22.

(c). De Sartre

68. This patent discloses an adaptive base drive that operates in saturation. This

adaptive base drive is generated through multiple paths and thus it is not a viable alternative

for a switching regulator. Nelson Testimony, 196:3–8; see Pl.’s Exh. 454.

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3. Other Prior Art Disclosed by LTC

69. LTC disclosed to the PTO all of the prior art that Nelson and Dobkin considered

relevant to the invention of the ‘741 patent. Nelson Testimony, 196:19–199:1, 200:3–19;

Pl.’s Exh. 120 at LIN 00058, LIN 00070–00075.

70. LTC disclosed multiple prior art items, including the LM117, the LM195, the

LT1005, the LT1001, and U.S. Patent No. 4,228,404, to the PTO during the original

prosecution of the ‘741 patent. Nelson Testimony, 197:4–24; Pl.’s Exh. 120 at LIN

00070–00119.

71. The LM117, the LM195, the LT1005, and U.S. Patent No. 4,228,404 were all

“boost” circuits, employing adaptive base drives that varied the base drive to a transistor. 

Nelson Testimony, 197:10–198:8; Pl.’s Exh. 120 at LIN 00071–00072.

72. The LT1001 employed a tied-back emitter in the transistor to limit the depth of

saturation of a transistor. Nelson Testimony, 169:21–24, 197:22–24, 198:9–12; Pl.’s Exh.

120 at LIN 00072. 

73. The LM117 is a regulator, but not a switching regulator like the LT1070. Dobkin

Testimony, 105:9–12. The transistor in the LM117 does not go into saturation. Dobkin

Testimony, 105:16–17.

4. Knowledge and Relevance of the SG1524, the LM119 and 

the LM111

74. In the first reexamination of the ‘741 patent (“Reexam I”), a third-party brought a

1976 publication by Mammano which described the operation of the SG1524 to the

attention of the Patent Office. The Patent office rejected claim 32 as anticipated by

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 Mammano. Reexam I, Paper No. 6 at LIN 00355. In response to the rejection, LTC

amended claim 32, narrowing the scope of the claim.

75. Claim 32 of the ‘741 patent was not included in the original patent application.

Nelson Testimony, 253:23–25. Claim 32 does not include the adaptive base drive circuitry

of the invention, nor does it include the tied-back emitter, but describes a modified Baker

clamp. Nelson Testimony, 254:8–256:2. 

76. This modified Baker clamp, with tighter control of the voltage drop in the circuit as

well as the ability to choose whether to have a negative or positive temperature coefficient,

allows the user of the transistor to control the forced beta in the switch. Prior to Nelson’s

invention, Baker clamps had resistors in the emitter base junction of the driver and power

transistor as opposed to within the circuit. Thus, when the current varied, transistors using

these prior Baker clamps would experience a voltage drop across the resistors with a

negative temperature coefficient—an outcome that was undesirable. Nelson Testimony,

254:15–256:2. 

77. In response to the rejection of claim 32, LTC recognized that the LM111 and LM119

contained circuits similar in structure to the circuit discussed in the Mammano article. 

Thus, LTC brought these two circuits to the examiner’s attention. Rowland Testimony,

949:2–20; Pl.’s Exh. 121 at LIN 00370–00378.

78. As part of that disclosure, Rowland (one of the prosecuting attorneys) stated,

“because the Examiner has apparently viewed Mammano as operating in saturation— which

. . . patentee believes is an erroneous understanding of Mammano— patentee hereby brings

the LM111 and LM119 to the attention of the Examiner.” This disclosure was based on

information conveyed to Rowland by Nelson and/or Dobkin. Rowland Testimony,

950:3–951:10; Pl.’s Exh. 121 at LIN 00376.

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79. Additionally, in its response to the PTO examiner’s rejection of claim 32 in light of

Mammano, LTC argued that Mammano is not intended to operate in saturation but that it is

possible, by careful selection of device geometries and voltages, to operate a transistor in or

out of saturation:

[The rejected claim] describes a circuit which (1) operates a transistor in saturation 

. . . Mammano, however, does not appear to work this way.

It is possible, by careful selection of device geometries and base-emitter voltages, to

cause Mammano’s circuit to operate transistor Q5 either in, or out of, saturation. 

Nothing in Mammano, however, states or suggests to choose those geometries and

base-emitter voltages so that any transistor in Figure 13—and, in particular,

transistor Q5—actually operates in saturation. . . . Mammano suggests, however,

that his circuit is designed to prevent transistor Q5 from going into saturation.

. . . Mammano also states that the circuit of Figure 13 is an “antisaturation network

for fast response . . .”. This statement, particularly coupled with the fact that

transistor Q5 is a driver transistor, suggests that the purpose of the circuit in Figure

13 is to prevent—rather than to cause and limit—saturation of transistor Q5. To

maximize the response or speed of the circuit of Figure 13 and transistor Q5, the

desire would be to operate transistor Q5 in its active region—not in saturation.

Pl.’s Exh. 121 at LIN 00366–00367

80. LTC admits that “the circuit configuration of Mammano is like that included in the

LM111 and LM119 devices.” Reexam I, Paper No. 8 at LIN 00376. See also Nelson

Testimony, 250:22–251:3. 

81. LTC did not disclose the LM111 and LM119 devices to the Patent Office in the

initial prosecution.

(a). SG1524

82. The SG1524 is a switching regulator controller with no power device. It was

originally manufactured by Silicon General. However, pursuant to a product exchange

agreement, LTC obtained manufacturing mask sets and documentation for the device from

Silicon General. Dobkin Testimony, 76:15–17, 76:21–77:2; Def.’s Exh. A-723; Pl.’s Exh.

457 at 3. Masks are the photographic plates used to place the particular pattern on a chip

during production. Dobkin Testimony, 77:18–19. 

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83. Using the masks and documentation provided under the product exchange

agreement, LTC manufactured an LTC version of the SG1524, with some modifications to

the chip design. Dobkin Testimony, 76:12–77:6, 77:20–24, 78:10–21. These modifications

related to undervoltage lockout circuitry and have no relation to the current dispute between

the parties. Dobkin Testimony, 77:3–9. 

84. Dobkin was familiar with LTC’s SG1524. Dobkin Testimony, 76:12–17, 78:10–21. 

Nelson was also familiar with the SG1524 because he reviewed the information that Silicon

General provided to LTC about the SG1524. Nelson Testimony, 205:18–24.

85. The LTC SG1524 employs an output transistor with a fixed base drive as opposed to

an adaptive base drive. Dobkin Testimony, 77:20–78:4. The output transistor of the LTC

SG1524 operates out of saturation. Id. at 78:7–15. Dobkin and Nelson both knew that the

SG1524 employed “clamp” circuitry that could be used to keep the drive transistor out of

saturation. Id. at 78:7–9; Nelson Testimony, 252:2–8. 

86. Based on tests of the propagation delay of the LTC SG1524 output transistor,

Dobkin determined that the output transistor did not operate in saturation. Dobkin

Testimony, 78:10–23, 110:24–111:9, 139:5–17, 144:18–22. Propagation delay is a

measurement of the time difference between the initiation and completion of the shut-down

process of a transistor. Nelson Testimony, 246:2–8. If propagation delay increases

considerably, then the device has begun to enter into saturation. Conversely an absence of

propagation delay problems indicates that the transistor is operating well out of the

saturation region. Nelson Testimony, 246:14–247:14. 

87. Dobkin did not conduct any direct tests of the LTC SG1524 or the Silicon General

SG1524 to determine whether it operated in or out of saturation—such as conducting

measurements of forced beta. Dobkin Testimony, 78:10–23; 110:25–111:9.

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88. The 1986 LTC SG1524 and the 1984 Silicon General SG1524 datasheets are

consistent with Dobkin’s understanding that the SG1524 products did not operate with the

output transistor in saturation. Dobkin determined that based on calculations of the output

transistor saturation voltage, these devices did not operate in saturation. Dobkin Testimony,

145:11–149:7; Def.’s Exh. A-323; Def.’s Exh. A-325; Def.’s Exh. A-715.

89. In the December 1985 Linear Newsline, publicizing the upcoming LT1070, LTC

compared the SG1524 to the LT1070, stating that “the fact that the LT1070 has only 5 pins

might suggest that it does not have many features compared to presently available control

chips like the SG1524 family. Au Contraire!!” Exh. 120 at LIN 00227.

90. Micrel’s expert witness Mr. McAlexander testified that in 1976, Mammano

described the SG1524 as employing “an anti-saturation, and that’s classically understood to

be a circuit that keeps the device out of saturation.” McAlexander Testimony, 819:23–

20:23; Def.’s Exh. A-723 at M002949. However, early industry usage of “anti-saturation”

differed from the use of the term in the patent at issue as the anti-saturation feature in the

‘741 patent is used to limit the depth of saturation. See Nelson Testimony, 202:20–24;

Dobkin Testimony, 109:23–110:1 (noting that the circuitry in the patent is “giving

controlled saturation or controlled anti-saturation, in the saturation region. It’s not keeping

it from saturation.”).

91. The adaptive anti-saturation feature of the ‘741 patent comprises the clamp circuitry

or the tie-back emitter in combination with the base drive. This circuitry controls the point

in saturation at which the transistor operates. Dobkin Testimony, 140:6–141:13. 

(b). LM119

92. The LM119 is a high-speed voltage comparator. Dobkin Testimony, 79:20–80:13. 

This is a specialized circuit that performs a comparison between two voltages, changing the

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output state of the circuit when one voltage exceeds the value of the other. Dobkin

Testimony, 79:24–80:11. Comparators are covered by the express terms of the ‘741 patent,

col. 13, ll. 7–15.

93. Dobkin designed the LM119 to use an output transistor with a fixed base drive as

opposed to an adaptive base drive. Dobkin Testimony, 80:14–21. Dobkin designed this

circuit while employed at National Semiconductor. Dobkin was employed as a circuit

designer at National Semiconductor for eleven years. Id. at 96:4–10. 

94. Dobkin wanted a transistor with a fast response and thus in his design of the LM119

Dobkin included a Baker clamp circuit to keep the output transistor out of saturation. 

Dobkin Testimony, 81:25–82:7, 111:25–112:10; Nelson Testimony, 252:14–16.

95. If the LM119 did not employ a Baker clamp, in extreme operating conditions the

output transistor of the LM119 might saturate. However the Baker clamp of the LM119

prevented it from saturating. Blauschild Testimony, 491:5–492:17; Pl.’s Exh. 121 at LIN

00375.

96. In order to ensure that the device was operating out of saturation, Dobkin and Nelson

conducted tests to measure the speed (or propagation delay) of the LM119. Nelson

245:17–20.

97. Nelson and Dobkin did not take any direct measurements of the LM111 and LM119,

such as attempting to compute forced beta. Nelson Testimony, 245:21–246:1, 247:10–18. 

Dobkin Testimony, 82:6–12.

98. Micrel has not introduced any evidence that would suggest that the output transistor

of the LM119 operated in saturation.

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99. Dobkin and Nelson did not think that the LM119 was relevant as prior art for the

prosecution of the ‘741 patent because it did not operate in saturation and employed

outdated technology. See Nelson Testimony, 200:7–19 (noting that he did not consider the

SG1524, LM119 and LM111 because they were designed for a particular purpose). At trial,

when asked why he did not disclose the LM119 as prior art, Dobkin responded:

A. I didn’t give any consideration. I didn’t even think of it.

Q. And, again, can you explain to the court why that’s something that would not

have occurred to a designer such as yourself?

A. Because what Mr. Nelson had done is he had run the transistor in

SAT[uration] to make the switching regulator more efficient. And he had

adaptively changed th drive to the circuit to make the SAT[uration] stay

constant over a wide range of loads, which was just different than any of

those earlier circuits. I didn’t even think of those. 

Dobkin Testimony, 82:17–25.

(c). The LM111

100. The LM111 was also a device manufactured by National Semiconductor. Pl.’s Exh.

121 at LIN 00374.

101. Although Dobkin did not design the LM111, he was familiar with the device

because he was the manager of the group that manufactured it. Dobkin Testimony, 83:2–8.

102. Prior to his employment at LTC, Nelson was also employed by National

Semiconductor. While employed by National Semiconductor, Nelson became familiar with

the LM111. Nelson Testimony, 204:20–205:6. After joining LTC, Nelson worked on

LTC’s version of the LM111. Id. at 205:7–8.

103. The LM111 is a voltage comparator like the LM119. Dobkin Testimony, 83:9–10;

Pl.’s Exh. 121 at LIN 00371.

104. Like the LM119, the LM111 employs an output transistor. The LM111 does not

employ an adaptive base drive for the output transistor. Dobkin Testimony, 83:11–12.

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105. Like the LM119, the LM111 operates out of saturation. It employs a Baker clamp

circuit which prevents it from saturating. Dobkin Testimony, 83:13–20, 144:18–22; Nelson

Testimony, 252:14–16; Blauschild Testimony, 491:5–492:17; Pl.’s Exh. 121 at LIN 00375.

106. Nelson took propagation delay measurements on at least one version of the LM111. 

Nelson’s propagation delay measurements showed that the output transistor of the LM111

did not saturate. Nelson Testimony, 245:15–20. Dobkin also tested the speed of the LM111

and concluded that it operated out of saturation. Dobkin Testimony, 83:15–20.

107. Micrel has not introduced any evidence that would suggest that the output transistor

of the LM111 operates in saturation.

III. INFRINGEMENT

A. The Invention

108. The ‘741 patent, issued on July 5, 1988, teaches that in many applications, in order

to optimize efficiency, it is desirable that a transistor operate in saturation during the oncondition. The patent states that “typically, minimum power dissipation, and optimum

overall efficiency, are achieved when the transistor is operated at a point near the edge of

saturation.” ‘741 Patent, col. 1, ll. 55–58. A transistor may be pre-set to operate in

saturation, with a pre-determined drive current and temperature. However, such a circuit is

vulnerable to either moving deeper into saturation, as excess base drive increases, or falling

out of saturation altogether. ‘741 Patent, col. 1, ll. 14–col. 2, ll. 19. 

109. The ‘741 patent, issued on July 5, 1988, teaches that in many applications, in order

to optimize efficiency, it is desirable that a transistor operate in saturation during the oncondition. The patent states that “typically, minimum power dissipation, and optimum

overall efficiency, are achieved when the transistor is operated at a point near the edge of

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saturation.” ‘741 Patent, col. 1, ll. 55–58. A transistor may be pre-set to operate in

saturation, with a pre-determined drive current and temperature. However, such a circuit is

vulnerable to either moving deeper into saturation, as excess base drive increases, or falling

out of saturation altogether. ‘741 Patent, col. 1, ll. 14–col. 2, ll. 19. 

110. The ‘741 patent, issued on July 5, 1988, is entitled “ADAPTIVE TRANSISTOR

DRIVE CIRCUIT.” 

[This] invention relates to a circuit for adaptively adjusting the operating point of a

transistor in saturation to maintain the forced current gain of the transistor within a

desired range throughout a desired range of load currents and operating

temperatures. More particularly, this invention relates to an adaptive transistor drive

circuit for use in association with a transistor switch subject to varying load

conditions and operating temperatures. 

111. ‘741 Patent, col. 1, ll. 5–13. In other words, the invention aims to give the user of

this drive circuit the ability to maintain an operating point in the more efficient region of

saturation at varying temperatures and current levels. 

112. Figures 3 and 5 of the ‘741 patent illustrate a switch circuit and an integrated circuit

switching voltage regulator, respectively, each utilizing an embodiment of the adaptive

transistor drive feature of the invention. ‘741 Patent, col. 3, ll. 29–31, 34–37. 

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113. In Fig. 3, a fixed current source I2 provides base drive sufficient to drive transistor

switch 300 into saturation at lower levels of collector current. However, the level of I2 is

not set high enough to drive switch transistor 300 into saturation at higher levels of collector

current. Thus, at low collector currents, the circuit is efficient. However, in order to

operate at higher collector current levels, extra circuitry is required to provide additional

base drive current. ‘741 Patent, col. 7, ll. 14–61.

114. The ‘741 invention provides another source of drive current I3 which, in conjunction

with I2 and functioning as an offset current, adapts the circuit automatically to variations in

collector current through switch transistor 300 to maintain a saturated condition. ‘741

Patent, col. 7, l. 62–col. 8, l. 26.

115. In Fig. 3, amplifier 311 senses the collector current flowing through series resistor

309 and increases drive current I3 as collector current increases. The total base drive current

thus adaptively increases as necessary to maintain the transistor’s operation in saturation at

higher collector currents. ‘741 Patent, col. 7, ll. 25–62. 

116. The invention also includes circuitry for preventing the switch transistor from

operating too deeply in the saturation region, as would happen if too much base drive

current is provided. Two examples are described in the ‘741 patent, both of which reduce

base drive current if the switch transistor begins to saturate too deeply. ‘741 Patent, col. 8,

ll. 27–51; col. 12, l. 31-col. 13, l. 3. 

117. In Fig. 3, an extra emitter 301 is added to the switch transistor 300. When the

transistor saturates, this emitter conducts current. By connecting this extra emitter to the

source of base drive current as shown in Fig. 3, the current conducted by the extra emitter

subtracts from the base drive current, reducing the base drive current that would otherwise

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reach the base of the transistor switch, thereby limiting the overdrive and depth of

saturation. The extra emitter is referred to in the ‘741 patent as a “tied-back emitter.” ‘741

Patent, Fig. 5 and col. 8, ll. 27–51. 

118. Similar to Fig. 1, in Fig. 5 the adaptive transistor drive circuit sums currents I2 and I3

from two current sources and adapts the circuit automatically to variations in collector

current through switch transistor 300 to maintain a saturated condition. ‘741 Patent, col. 9,

l. 20–col. 11, l. 61.

119. Fig. 5 illustrates an alternative circuit (circuit 572) for limiting the depth of

saturation. Fig. 5 is a simplified drawing of the circuitry used in the LT1070. ‘741 Patent,

col. 12, ll. 35–40; Nelson Testimony, 186:22–190:7. In this circuit, transistor 578, current

source 574 and diode 580 are arranged in a loop with the collector-base voltage of switch

transistor 300 and the base-emitter diode junction of drive transistor 306. ‘741 Patent, col.

12, ll. 49–53.

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120. Current source 574, resistor 576, and transistor 578 operate like a low voltage

diode—with a diode voltage drop of approximately 0.3 volts. ‘741 Patent, col. 12, ll.

44–46. To prevent the transistor from falling too deeply into saturation, transistor 578 and

diode 580 conduct current away from the base drive transistor, thus reducing the base drive

current that would otherwise overdrive the base of switch transistor 300. ‘741 Patent, col.

12, ll. 58–66. 

121. In essence, the goal of the ‘741 patent is to provide an adaptive transistor drive

circuit which, through the pre-determination of desired variables—such as the ratio of

collector to base current—works to maintain the transistor’s point of operation “within a

desired range of a chosen point in saturation.” Consequently, the efficiency of a switch is

optimized or the efficiency of an integrated circuit switching voltage regulator circuit is

improved. ‘741 Patent, col. 2, ll. 30–40, 44–57, 64–68. 

B. Saturation

122. The only dispute with respect to infringement is whether Micrel’s devices operate in

saturation. Micrel has stipulated that all other elements of all asserted claims of the

patent-in-suit are met. Blauschild Testimony, 365:17–366:7. 

123. During the limited claim construction performed by this court in 2004, the court

found that the heart of the parties’ dispute lay in (and hence the issue of infringement turned

on) the construal of the phrase “in saturation.” In its January 2004 claim construction order,

the court determined that the phrase “in saturation” specified that “the art [is operating]

expressly and exclusively in the region of saturation. Thus, where ‘in saturation’ is used in

a ‘741 patent claim, it is used to denote the working of the covered invention consistently at

a state of forced current gain.” Claim Construction Order, Def.’s Exh. A-224 at 17:3–6.

124. Although in its claim construction order the court provided some guidance with

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respect to the region of saturation and the onset of saturation, the court did not specify

whether the “knee” or “elbow” region of the lines in Fig. 1— representing output

characteristics of a typical silicon bipolar junction transistor as a function of the base

current—are in saturation. These characteristics lines are labeled 100, 102, 104, 106, 108

and 110 in Fig. 1 below. Micrel’s accused products operate on the knee of the

characteri

stic

curves. 

FIG. 1

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1. The ‘741 patent’s Characterizations and Definitions of “in

Saturation”

(a). Line 112 of Figure 1

125. The ‘741 patent describes three operating regions for a transistor in Figure 1: the

cutoff region, the active region, and the saturation region. ‘741 Patent, col. 3, ll. 53–55;

Blauschild Testimony, 330:6–12.

126. In the section entitled “DETAILED DESCRIPTION OF THE INVENTION,” the

patent teaches that the “shaded area 101 between line 100 and the ordinate of the graph is

the cut-off region” and that the “active region” is “represented by the shaded central region

of graph 103.” The ‘741 patent states that the “saturation region” is “defined by the

saturation line 112 in FIG. 1.” ‘741 Patent, col. 3, ll. 65–col. 4, ll. 21. (emphasis added). 

127. Micrel’s contention that Line 112 itself comprises the entire area of saturation is not

supported by the patent terms or by scholarly texts. Line 112 “sets the [outer] boundary of

saturation. . . . you can decrease the voltage across the transistor going left to right here, and

you could go along any curve, but you can’t go past that boundary.” Blauschild Testimony,

340:22–25.

128. Further, as discussed infra, a person of ordinary skill in the art would not understand

the saturation region to be limited to Line 112. 

129. In support of Micrel’s position that operation on the knee of the curve is not in

saturation, McAlexander asserted that Fig. 1 had a fourth region of operation—the

“transition” region. See Pl.’s Exh. 456; McAlexander Testimony, 879:25–16, 880:16,

881:6–10. 

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130. Essentially, by arguing that there is such a transition region, McAlexander seeks to

create a gap between the end of the active region and saturation and thus create a space

wherein Micrel can operate without infringing the ‘741 patent. Pl.’s Exh. 456; Trial

Testimony, 880:8–10, 885:2–7. 

131. However, this novel position is wholly unsupported. As McAlexander conceded at

trial, the ‘741 patent makes no mention of a transition region. McAlexander Testimony,

880:14–23. The only regions specified are the cutoff, active and saturation regions. ‘741

Patent, col. 3, ll. 53–55. 

132. Further, a person of ordinary skill in the art would not have understood there to be a

transition region. None of the textbooks proffered during trial identified a transition region

and McAlexander provided no evidentiary support for this proposition. Blauschild

Testimony, 2055:11–2056:21.

(b). ‘741 Patent’s Formula Denoting Onset of Saturation

133. The ‘741 patent provides a formula to determine the onset of saturation: “The

saturation region commences for any particular collector current when the base current IB

multiplied by hFE is equal to ICSAT, where hFE is the DC collector base current gain and ICSAT

is the current through the collector.” ‘741 Patent, col. 3, l. 66–col. 4, l. 2 (emphasis added). 

In other words, saturation begins when IB X hFE = ICSAT. 

134. hFE is the specific current gain in the transistor for the active region. ‘741 patent, col.

3, l. 66–4, l. 2; Pl.’s Exh. 455 (Slides 19–21); Blauschild Testimony, 341:3–342:7.

135. A person of ordinary skill in the art would understand that hFE is a reference to the

transistor’s current gain in the active region. Textbooks written in this area provide support

for this proposition. Pl.’s Exh. 455 (Slide 22); Blauschild Testimony, 342:17–343:7.

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136. Based upon the above-stated formula in the ‘741 patent, the saturation region

commences where an active region value of collector current (IB multiplied by hFE ) is equal

to a saturation region value of collector current (ICSAT ). Since hFE is defined only in the

active region, there is only one point where this occurs, and it is the point at the end of the

active region. The saturation region therefore includes the curve leading to the active

region. Pl.’s Exh. 455 (Slide 27); Blauschild Testimony, 343:21–344:17. 

137. Micrel misconstrues the function of this equation when it asserts that the Accused

Products do not “meet this criteria.” The equation purports to describe the onset of

saturation for a particular base and collector current and not to determine if a chosen

operating point meets the requirements of the equation. An operating point would only

satisfy the requirements of the equation if it operated at the point when saturation

commenced—per the specifications of the patent. See McAlexander Testimony,

746:16–747:12; Blauschild Testimony, 2053:18–2055:7. 

138. The notion that saturation commences at the boundary between the straight line of

the active region and beginning of the curve is consistent with the court’s claim construction

order. 

As the ‘741 patent makes clear, the edge of saturation is a gradual one, beginning

where the active region ends and curving at the point at which base current is

diverted to the collector. For any base current level, saturation depth increases as the

operating point of the transistor moves down and left along the curve of the base

current line. 

Def.’s Exh. A-224 at 18 n.3; see also Pl.’s Exh. 455 (Slide 28); Blauschild Testimony,

344:18–345:6.

139. The “edge of saturation” is the point at which the transistor leaves the active region

and enters saturation—the point when base current begins to be diverted to the collector. 

Blauschild Testimony, 159:23–360:17. The deeper a transistor is in saturation, the greater

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the diversion of base current to collector current. Blauschild Testimony, 360:22–361:1.

140. This teaching is consistent with how saturation has been taught and described to

persons of ordinary skill in the art. Pl.’s Exhs. 199, 246–248, 255, 460, 455 (Slides 29–33);

Blauschild Testimony, 339:3–22, 345:7–18; McAlexander Testimony, 886:13–888:23. 

(c). Series Model Approximation

141. Fig. 2 of the ‘741 patent shows an approximation of the “elbow” or “knee” of one of

the characteristic output lines of Fig. 1. Horizontal line 202 represents an “approximation of

transistor operation in the saturation region” and vertical line 200 is “an approximation of

transistor operation in the active region. The actual curve that an operating transistor

produces is represented by line 204. ‘741 Patent, col. 4, ll. 51–65; Blauschild Testimony,

345:22–346:2. 

142. The ‘741 patent describes a theoretical operating point where line 200 and 202

meet—point QM. This is not an actual operating point, but a theoretical point on the

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approximated model of a transistor. Blauschild Testimony, 346:5–10. Point QM

approximates the “onset of saturation.” ‘741 Patent, col. 4, ll. 65–68.

143. The ‘741 patent states that “at a collector current IC corresponding to operating point

QM, the actual transistor will operate at a collector-emitter voltage VCE, which is higher than

that predicted by the series resistance model.” In other words, for a given collector current,

the transistor will operate at a less efficient point—with a higher voltage than that of the

series model. Indeed, the patent notes that cross-hatched area 208 represents the “overall

difference in efficiency between the actual transistor and the series resistance model.” ‘741

Patent, col. 5, ll. 1–16. When a base current is applied that would theoretically cause the

transistor to operate at point QM, the transistor will actually operate where lines 200 and 204

meet. 

144. The ‘741 patent states that to “overcome the difference in efficiency, the actual

circuit must be designed to drive the transistor [from the operating point on the actual curve

204 corresponding to QM] to an operating point deeper into saturation to ensure operation

in the saturation region.” ‘741 Patent, col. 5, ll. 1–16 (emphasis added). 

145. Thus, the patent describes the operating point on the actual curve that corresponds to

point QM—the highest point on figure 2—as being in saturation. Accordingly, all the points

on curve 204, from the highest point to the origin, are in saturation. Pl.’s Exh. 455 (Slides

34–36); Nelson Testimony, 185:25–186:21; Blauschild Testimony, 345:19–347:9.

146. The fact that the patent teaches that points 116, 118, 120 and 122 are operating

points “near the edge of saturation” is consistent with the foregoing. To keep the device

from falling out of saturation and into the active region, the patent teaches that the invention

drives the device deeper into saturation to “ensure” operation in saturation. See ‘741 Patent,

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col. 5, ll. 1–16. Thus, the edge of saturation begins at the highest point of the curve

204—the end of the active region. The illustrative operating points are all lower on the

curve and thus they operate deeper in saturation and close to this “edge of saturation.” See

‘741 Patent, Fig. 1.

(d). Forced Current Gain/Forced Beta

147. The current gain ($) of a transistor is the ratio of collector current IC to base current

IB. ‘741 patent, col. 4, ll. 24–26. 

148. Forced current gain is “the current gain of a transistor in saturation . . . [which has

been] forced lower by excess base current.” ‘741 patent, col 4., ll. 33–35. The current gain

is “forced lower” because when a transistor is operating in saturation, the drive current

provided to the transistor exceeds the value necessary to produce the collector current IC

which results.” ‘741 patent, col. 1, ll. 39–45. In other words, in the saturation region, to

achieve the same level of current that was achieved in the active region, an excess of base

current must be applied. Blauschild Testimony, 363:2–5. Thus, the ratio (or current gain)

results in a lower value since the denominator in the equation—the base current—has

increased significantly. 

149. The practical way to measure saturation is through computations of forced beta. It is

possible to measure the base and collector currents of a transistor. The operating points of

the transistor on a curve can also be measured, and it can be determined whether there is

excess base current, indicating saturation. Nelson Testimony, 183:7; Blauschild

Testimony, 352:22–353:4.

150. Using Fig. 1 to illustrate, the patent teaches that “when a transistor is operating on

the saturation Line 112, an increase in base current IB does not result in an increase in

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collector current IC.” ‘741 Patent, col. 5, ll. 50–53. Similarly, in the knee portions of the

lines on Fig. 1, excess base current is required to operate at the same level of collector

current. Blauschild Testimony, 369: 6–8. 

151. In the active region, changes in voltage result in small changes in current. However,

in the saturation region, a small change in voltage results in a substantial change in current. 

Blauschild Testimony, 375:5–12.

(e). Forward Bias

152. This court’s claim construction found that “[i]n the context of the ‘741 patent,

‘saturation’ denotes a state of forced current gain in which both the emitter-base and

collector-base junctions of a transistor are forward-biased.” Def.’s Exh. A-224 at 12:16–21

(emphasis added). The patent states that another way of characterizing saturation is that

both emitter-base and collector-base junctions are forward biased. ‘741 Patent, col. 4, ll.

2–5.

153. In a transistor, the base-emitter diode is at the junction between the base and the

emitter terminals and the base-collector diode is at the junction between the base and the

collector terminals. Diodes are one-way valves which either permit current to flow or

prevent it from flowing. McAlexander Testimony, 689:15–692:19.

154. In the cut-off region neither the base-emitter nor the base-collector diodes conduct

current. In the active region the base-emitter diode conducts current, but the base-collector

diode does not. In the active region, the base-collector junction is reverse biased and there

is no resultant current flow. The reverse biased region corresponds with the straight section

of the characteristic output line. Blauschild Testimony, 358:11–359:25. 

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155. In the saturation region, both the base-collector and the base-emitter diodes conduct

current—they are forward biased. In this latter situation where both diodes are forward

biased and conducting an appreciable amount of current, the transistor is referred to as being

in a state of forced current gain. McAlexander Testimony, 696:17–21. Forced current gain

is achieved when both junctions are forward biased. Blauschild Testimony, 433:11–22. 

156. “Forward biasing” is understood by a person of ordinary skill in the art to mean that

there is enough positive voltage across the junction to cause significant current flow, which

is current flow that can be observed or measured. Blauschild Testimony, 347:24–348:4.

157. Engineers make a distinction between forward bias and positive bias. Although a

junction may have some positive voltage, it is not considered forward biased until there is a

measurable effect—some significant current flow. Blauschild Testimony, 359:16–20;

435:4–8. 

158. During prosecution, LTC represented to the PTO that forward bias occurs “when the

junction becomes so positively biased that a significant portion of base drive provided to the

transistor is diverted to the transistor’s collector.” Def.’s Exh. 123 at 838 (emphasis added).

159. The claim construction provides that a transistor is thus in saturation when the

collector-base junction becomes so positively biased that a substantial portion of base drive

is diverted to a given transistor’s collector.” A-224 at 10:16–24 (emphasis added). At trial,

Nelson also testified that the term forward biased describes a condition whereby the

collector-base junction is conducting “a significant amount of current.” Nelson Testimony,

212:9–215:19 (emphasis added). At trial, LTC’s expert, Blauschild, testified that forward

biasing occurs when there is the flow of “appreciable current.” Blauschild Testimony,

435:22 (emphasis added).

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160. Micrel’s attempts to draw a distinction between LTC’s use of “significant” during

prosecution and “appreciable” at trial is unpersuasive. LTC’s positions during prosecution

and at trial are not inconsistent. The Oxford English Dictionary defines appreciable as

“capable of being estimated, weighed, judged of, or recognized by the mind.” The Oxford

English Dictionary 581 (2d ed. 2001). “Significant” is defined as something “important,

notable.” Id. At 458. Consequently, this court’s determination that forward biasing. occurs

when a “substantial” amount of base drive is diverted to the collector still holds. Forward

biasing occurs when the junction of a transistor becomes so positively biased that a

measurable, and therefore substantial, amount of base drive is diverted to the collector.

161. Further, the way in which diodes operate, as illustrated by Blauschild in Def.’s Exh.

486 (slide 3), demonstrates that there is measurable current from the diode which

commences at a point after the origin and later increases exponentially. The characteristics

of a diode’s operation is represented by a line that curves upwards, away from the origin. 

This is because the physics of a diode specify that once a diode reaches a forward bias point,

it starts to increase gradually. The diode has an exponential characteristic, so a curve

results. Def.’s Exh. 486; Blauschild Testimony, 2048:14–19. 

162. The court does not find McAlexander’s expert opinion on the physics of diode

operation credible. McAlexander asserts that the diode characteristic is initially

represented by a horizontal straight line with no appreciable current and then at the point of

forward biasing by a vertical line representing substantial current. See McAlexander’s

Testimony, 692:25–693:12. The model presented by Micrel to support this proposition is a

simplified model which does not offer the actual performance characteristics of a diode. 

Blauschild Testimony, 2088:25–2090:2

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163. The base-collector junction of a transistor is forward biased when the operating point

of the transistor is on the curved portion (i.e., the knee or elbow) of the transistor’s output

characteristic line. This is confirmed by textbooks and teaching materials. Blauschild

Testimony, 347:24–349:8, 357:21–361:3; Pl.’s Exh. 455 (Slides 44–45, 46); Pl.’s Exhs. 255,

257.

164. The curve in the characteristic output line of a transistor is caused by the basecollector junction forward biasing and thus saturation includes all points on the curve

leading up to the boundary with the active region. Blauschild Testimony, 347:14–23; ‘741

patent, col. 4, ll. 2–5); Pl.’s Exh. 455 (Slides 42–43). 

165. It is not correct, as Micrel has asserted, that a base collector junction requires a

positive voltage of approximately 0.6–0.7 volts to be forward biased. The ‘741 patent

describes a transistor being in saturation at a base-collector voltage of 0.3 volts. ‘741

Patent, col. 12, ll. 58–64; Pl.’s Exh. 455 (Slides 50-52); Blauschild Testimony,

353:5–357:20.

2. Instantaneous Change From Cutoff to Saturation Line 112 is

Unsupported

166. The ‘741 specification states: “An ideal switch is one which is capable of controlling

a wide range of switch currents with no power dissipation and with an instantaneous

transition from a conducting state to a non-conducting state and vice versa.” ‘741 patent,

col. 1, ll. 18–21. In actuality, the patent teaches, transistors do not fit the ideal description

of a switch that transitions instantaneously. See ‘741 Patent, col. 1, ll. 22–26. Transistors

“most closely approximate an ideal switch when operated in the saturation region during the

‘on’ condition of the switch and in the cut-off region during the ‘off’ condition of the

switch.” ‘741 Patent, col. 1, ll. 22–26.

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167. Micrel’s expert testified that in order to approximate an ideal switch, the transistor

must make a virtually instantaneous change from cutoff to saturation, without any

measurable amount of base current and without going into the active region. McAlexander

Testimony, 671:21–673:5; 674:6–12; 676:5–678:13; and 826:13–832:12. However, the

patent expressly states that there is a period of approximately 50–500 nanoseconds when

transistor 300 is being turned on where “transistor 300 is driven from a cutoff state to at

least the active region of operation.” ‘741 Patent, col. 8, l. 65–col. 9, l. 1 (emphasis added). 

168. The patent teaches that in the drive circuit of Fig. 3, current source 312 initially

generates a current I2 which is increased after a short delay to I2'. This “short delay” is also

specified as consisting of 50–500 nanoseconds—the same period of time in which we are

told the transistor moves from the cutoff region to at least the active region. ‘741 Patent,

col. 7, ll. 36–40. The initial current (I2) is enough to turn on transistor 300 when the voltage

across the transistor (VCE) is high— as in the case when transistor 300 is off. ‘741 Patent, 

col. 7, ll. 41–47. As the patent states, current source 312 of Fig. 3 “generates current I2

when transistor 300 is off and I2' when transistor is on.” ‘741 Patent, col. 8, ll. 54–55. As

discussed supra, I2' is sufficient to drive the switch into saturation at low currents and nonextreme room temperatures. ‘741 Patent, col. 8, ll. 1–4. The variable current I3 is added to

help drive the transistor into saturation at higher currents and temperatures.

169. The transistor must enter the active region before reaching its operating point in

saturation because once transistor 300 is turned on, VCE will start to come down as the

transistor begins to conduct collector current. To conduct collector current, the transistor

cannot remain in the cutoff state. It must enter at least the active region. See Fig.1 (an

increase in collector current without a concomitant decrease in voltage would necessarily

place the transistor in the active region of operation). Then, once the transistor is on and

conducting collector current and VCE starts to come down, the base current I2 is increased to

I2'. The combination of I2' with the variable current I3 is what drives transistor 300 into, and

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maintains it in, saturation. VCE does not move from a high to low instantaneously, but only

after a “short delay.” ‘741 Patent, col. 7, l. 41–48, l. 26; Blauschild Testimony,

2059:24–2060:13, 2063:5–14. 

170. Micrel is incorrect in its assertion that to find that a transistor enters the active

region, for a brief moment as it turns on, is contrary to the asserted claims of the ‘741

patent—which require that the transistor operate exclusively in the region of saturation. 

McAlexander Testimony, 839:5–841:16 and 918:3–920:14; Claim Construction Order,

Def.’s Exh. A-224 at 17:3–4. The patent does not teach that the transistor operates in the

active region, but merely that in reaching its operating point it passes briefly through the

active region—as it must with an increase in collector current. Thus, although the

transistor must start off going into the active region, the combination of the fixed and

variable base currents provided by the adaptive base drive circuitry ensures that the

operation point is in saturation. Blauschild Testimony, 2064:20–2067:6. 

171. Blauschild’s oscilloscope trace does not lend support to McAlexander’s theory

regarding the virtually instantaneous transition of a transistor from cutoff to saturation as it

is a simplified model utilizing a filter and a low frequency scope. These limitations

preclude an accurate illustration of the transistor’s operation. The simplified oscilloscope

trace appears to demonstrate that when base current is applied to the Micrel transistor,

collector-emitter voltage falls to zero almost instantaneously, without significant collector

current. McAlexander Testimony, 833:18–834:20 and 925:3–928:12; Pl.’s Exh. 455 at

slide 116; Blauschild Testimony, 2095:2–2097:10; Def.’s Exh. A-1033.

C. Micrel’s Accused Products Infringe the ‘741 Patent 

172. The parties have agreed that the structure that is in each one of the accused devices

is essentially the same, and for purposes of infringement, determination of infringement or

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non-infringement on one device would apply equally to the others. McAlexander

Testimony, 731:8–15, 731:2–8.

173. Therefore, the analysis below regarding the MIC2172 also applies to the MIC3172

and the MIC2172, which share the same infringing circuitry as the MIC2172. Pl.’s Exhs,

125, 126.

174. The test results discussed below demonstrate that the claimed circuitry in the

accused MIC2171, MIC2172 and MIC3172 products operates on the knee of the output

characteristic line. See, e.g. Def.’s Exh. A-560 (reproduced below) which demonstrates

graphically the operating point of the MIC2172. The test results also demonstrate that at the

operating points of these devices, both junctions are forward biased and operating in a state

of forced current gain.

175. The graph below only represents a small sub-section of the characteristic output line

of the MIC2172. Specifically, only a small fraction of the active region is represented

graphically. On a larger scale graph, if the full active region were to be plotted, then the

curved areas of the graph would likely “smouch[sic] together . . . [forming] a line.” 

Blauschild Testimony, 337:13–21.

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1. LTC’s testing of the MIC2172 Demonstrates Operation in

Saturation

176. LTC’s technical expert, Blauschild, tested MIC2172 parts using two test methods. 

Blauschild Testimony, 371:6–25.

177. Blauschild reviewed the patent, the claim construction order and Micrel’s testing

results of the MIC2172 parts. After reviewing this information, and after conducting his

own tests of the MIC2172, he concluded that the MIC2172 meets all of the requirements of

the asserted claims of the ‘741 patent. Blauschild Testimony, 327:14–15. 

178. Blauschild first tested the MIC2172 using the Typical Application shown in Fig. 1 of

the Micrel 2172 datasheet. Blauschild measured two MIC2172 parts. The MIC2172 switch

transistor operated in saturation. Pl.’s Exh. 455 (Slides 113–18); Blauschild Testimony,

372:6–377:5.

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179. Blauschild conducted further tests on one of the MIC2172 parts and concluded that it

operated in saturation. Blauschild noticed that when he varied voltage slightly, there was a

substantial change in collector current—suggesting that the transistor was operating in

saturation. Pl.’s Exh. 455 (Slide 119); Blauschild Testimony, 376:15–377:5; 377:6–381:21.

180. Blauschild also tested an LTC LT1172 part. The results confirm that the switching

transistor in the LT1172 operates in saturation. Pl.’s Exhs. 243, 344 (Slide 122); Blauschild

Testimony, 371:6–10, 377:6–15, 377:7–9, 380:9–381:20, 485:18–489:23.

181. Blauschild further demonstrated, using Micrel’s own measurements, that the

MIC2172 operates in saturation because it produces excess base current—“. . . the drive

current provided to the transistor exceeds the value necessary to produce the collector

current IC which results . . . .” ‘741 patent, col 1, ll. 39–45; Pl.’s Exh. 455 (Slide 60);

Blauschild Testimony, 367:2–369:15. Thus, for any given operating point of the Micrel

2172, one could achieve the same collector current if one were to operate in the active

region. 

182. Blauschild found that at 7.7mA (with 880mA of collector current), one could

achieve the same 880mA of collector current with a 6.9 mA base current. Thus, at 7.7mA,

the MIC2172 generated 0.8 mA of excess base current. Similarly, Blauschild found that at

9.2 mA, the MIC2172 generated 2.3 mA of excess base current. Pl.’s Exh. 455 (Slide 60);

Blauschild Testimony, 368:22–369:15.

183. Blauschild used Micrel’s test data to show that the current gain at the operating

points for the Micrel parts was reduced by about 20% from the current gain in the active

region. The current gain in the active region was almost 125, while current gain on the knee

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of the curve was approximately 98. Pl.’s Exh. 455 (Slide 111); Blauschild Testimony,

369:16–22.

2. Micrel’s Testing of the MIC2172 Demonstrates Operation in 

Saturation

184. Micrel’s technical expert, Joseph McAlexander, also tested the MIC2172 parts. 

McAlexander Testimony, 731:14–22.

185. McAlexander tested the MIC2172 by removing the top of the package and plotting

the device’s response to different currents and voltages. McAlexander Testimony,

731:19–732:5.

186. McAlexander first measured the switching transistor (connected as it normally

operates) to obtain the operating point. McAlexander Testimony, 732:6–9.

187. McAlexander then disconnected the controlling circuitry from the switching

transistor and used probes to vary the current and voltage conditions applied to the

transistor. This allowed him to make additional measurements—specifically to determine

what current level needed to be applied to the base to achieve the particular operating point. 

Def.’s Exh. A-560; McAlexander Testimony, 732: 10–17.

188. McAlexander performed these measurements at three different values of base current

(6.9 mA, 7.7 mA, and 9.2 mA) indicating each measured operating point with an “X.” 

Def.’s Exh. A-560, A-561, A-562; McAlexander Testimony, 736:17–22.

189. For each of the three values of base current, the measured operation point was

towards the bottom of the knee or elbow, thereby demonstrating that the Micrel products

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operate in saturation. Def. Exhs. A-560, A-561; Blauschild Testimony, 363:12–365:5;

McAlexander Testimony, 736:17–22; 734:20–23. 

190. McAlexander conceded that at the operating points of the Micrel parts, there will be

conduction of current from the base to the collector that contributes to the reduction in

current gain. McAlexander Testimony, 852:2–853:13.

191. At trial, in demonstrating that Micrel’s operating points do not meet the formula

outlined in the patent for the “onset” of saturation, McAlexander presented a calculation that

confirmed the Micrel parts are in saturation. McAlexander testified that the average beta in

the active region for a MIC2172 is 125. Then he demonstrated that at a base current of 9.2

mA, the ratio of collector current to base current at the operating point of the Micrel part

was 93 (IC/IB = 860/9.2). This is a reduction in current gain of 34 percent from the current

gain of 125 in the active region—indicating that the MIC2172 operates in saturation. Def.’s

Exh. A-559; McAlexander Testimony, 747:5–748:25.

192. The Micrel engineer responsible for the MIC2172, Bud Miller, performed tests

during design of the MIC2172 part that also showed the part to be in saturation. Referring

to data in the datasheet for the Micrel part, taken from measurements he made, Miller

calculated that the switching transistor in Micrel’s part typically operated with a current

gain of 111. The datasheet also showed that the current gain could be as low as 50. Miller

testified in deposition prior to trial that beta of a transistor in Micrel’s process ranged from

125 to 300. Thus, Miller’s data showed that the switching transistor in Micrel’s part was

operating at a reduced current gain, i.e., a forced current gain, and therefore was in

saturation. Def.’s Exh. A-394; Miller Testimony, 597:3–599:1; 632:14–634:24.

193. Miller understood when he designed the MIC2172 that reduced current gain was a

significant indicator of saturation. Miller Testimony, 592:10–593:6. 

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194. At trial, Miller claimed that a “standard” for saturation existed for “discrete”

transistors under which current gain had to be reduced to a value of 10. Micrel did not offer

any evidence in support of this purported industry standard and Miller made no reference to

such a standard in his deposition testimony. Moreover, the ‘741 patent, of which Miller was

aware, clearly described examples of forced current gain values in excess of 10, and showed

saturation occurring at current gain reduction of about 20 percent, approximately the same

as in the Micrel products. Miller Testimony, 593:1–25, 62:6–630:9; Blauschild Testimony,

2068:1–2069:25; ‘741 Patent, col. 1, ll. 62–12, l. 7. 

195. McAlexander does not disagree with the results of Blauschild’s testing, and

reproduced the testing using Mr. Blauschild’s method. Similarly, Mr. Blauschild does not

disagree with Mr. McAlexander’s results. Blauschild Testimony, 451:8–19; McAlexander

Testimony, 749:14–750.

196. Tim Rust (a Micrel engineer) testified that the Micrel devices do not operate in the

active region. Rust Testimony, 1603:4–12. At trial, when McAlexander was asked if his

results were operating in the active region (since Micrel was unwilling to concede that their

devices operated in saturation), he was unable to give a definitive answer. Rather, he stated,

“. . . I would much prefer to say it is operating not in the saturation region, according to

what the claimed invention requires.” McAlexander Testimony, 751:24–752:3; 737:7–12.

However, this statement is inconsistent McAlexander’s other statements with respect to

Micrel’s operating points. McAlexander also asserted that the accused devices operate off

their saturation line and “come up an entirely different slope . . . [towards the] active

region.” McAlexander Testimony, 744:20–745:6. This understanding, McAlexander

asserts, is confirmed by Blauschild’s oscilloscope trace, which shows that after Micrel’s

operating point goes down to the ordinate, it rises at an angle above the saturation line and

then levels off, eventually reaching a point on the knee of the characteristic curve. Implicit

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in this argument is a concession that Micrel is operating in the active region—something

which Micrel does not assert and thus is understandably not willing to admit to. It is for this

precise reason that McAlexander created a transition region of operation, wherein the

Accused Products would not infringe. 

197. In summary, the Micrel accused devices infringe the asserted claims because LTC’s

and Micrel’s testing show that over a range of collector currents and operating temperatures,

the switching transistor of the Accused Products consistently operates in saturation.

D. Micrel’s Testing of a 1990 SG1524 is Irrelevant to an Infringement

Analysis

198. As part of its non-infringement arguments, Micrel offers evidence of testing it did on

an SG1524 part made by Silicon General in 1990. A 1976 version of this part was

referenced in a Mammano article brought to the attention of the PTO during prosecution. 

See Section II.C.4. ¶ 80. Micrel contends that LTC admitted during prosecution that the

SG1524 does not operate in saturation, and that the SG1524 that Micrel tested operates at a

point closer to saturation than Micrel’s Accused Products—specifically at a point lower on

the knee of the characteristic output curve of a transistor. 

199. Micrel’s testing of a SG1524 made by Silicon General in 1990 is irrelevant to

whether Micrel infringes the ‘741 patent because Micrel did not establish that the 1990 part

it tested operates the same as any SG1524 part known to LTC, or in the same way as the

1976 Silicon General part described in the Mammano paper. 

200. There is no guarantee that the part described in the 1976 Mammano paper is the

same as the 1990 part which Micrel tested. McAlexander Testimony, 891:3–24.

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201. In support of his opinion that the LT SG1524 was the same as the 1976 Silicon

General SG1524, McAlexander claimed that he compared the schematics for the Linear

Technology SG1524 shown on the 1990 LTC datasheet with the schematics shown in

Figure 13 of the 1976 Mammano Paper. Pl.’s Exh. 458, Figure 13; Pl.’s Exh. 715 at 7–9;

McAlexander Testimony, 901:19–902:5.

202. However, McAlexander admitted that R51, shown in the LT1524/SG1524

schematics does not appear in the Mammano paper. McAlexander Testimony, 903:3–16.

203. McAlexander also admitted that the capacitor C7 that is shown in the Linear

Technology Diagram is also not shown in the Mammano paper. McAlexander Testimony,

903:18–904:3.

204. McAlexander conceded that at the schematic level the SG1524 manufactured by

LTC was different from what was described by the Mammano paper because of the

presence of additional components. McAlexander Testimony, 904:18–22.

205. As Blauschild explained, if transistors are different sizes, or are made by different

processes, they may have different operating points, and one may be in saturation while the

other may operate in the active region. Pl.’s Exh. 455 (Slide 50); Blauschild Testimony,

351:24–362:21.

206. The 1976 Mammano article did not disclose the sizes of the transistors or resistors in

the Silicon General SG1524 circuit. Def.’s Exh. A-723; McAlexander Testimony,

889:9–14. Therefore, without this information, an accurate comparison of the 1976 SG1524

cannot be made with the LTC SG1524 or Micrel’s accused devices. 

207. In any event, Micrel incorrectly relies on statements made by LTC during

prosecution. LTC did not admit during prosecution of the ‘741 patent, or during

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prosecution of any reexamination proceeding relating to the ‘741 patent, that the specific

SG1524 measured by Micrel did not operate in saturation. 

208. During prosecution, LTC argued that the SG1524 discussed in the Mammano paper

was modeled to operate out of saturation, but could be designed to operate in saturation. 

See Section II.A.2.4.(a) ¶¶ 74–77 supra. There was no distinction made by the parties or by

the PTO examiner between operation on saturation Line 112 and operation off saturation

Line 112. Moreover, LTC did not specify whether the operating point of this 1976 SG1524

was in or out of saturation. 

209. LTC believed that the SG1524 part (with which Dobkin was familiar) operated in

the active region and not in the knee. Dobkin’s testing of delay times on the LTC SG1524

showed that that part was not in saturation, which is consistent with his understanding of

LTC’s SG1524 datasheets. Dobkin Testimony, 78:10-23, 110:24–111:9, 139:5–17,

144:18–22; Nelson Testimony 246:2–8.

210. Further, Dobkin testified that if the 1990 Silicon General SG1524 tested by Micrel

was operating in the elbow, there would be excess base current and it would be in

saturation. Dobkin Testimony, 138:21–139:17.

211. For the foregoing reasons, the court will not consider the testing of the 1990 SG1524

in its infringement analysis.

E. Conclusion

212. After a thorough review of the patent specifications, claims, prosecution history and

extrinsic evidence presented at trial, this court finds that the Accused Products all operate

expressly and exclusively in saturation. Micrel’s Accused Products literally infringe all the

asserted claims of the ‘741 patent.

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II. DAMAGES

A. Intervening Rights

213. Micrel, in seeking a reduction to the damages owed to LTC, asserts that it is entitled

to absolute as well as intervening rights for Accused Products that were shipped or in

inventory at the time of the B2 Certificate’s issue. Micrel also contends that it is entitled to

equitable intervening rights for the amount it spent in substantial preparation of these

products. 

214. Inventory can be calculated by taking the difference between the number of

integrated circuits made and the number of integrated circuits sold. Dragun Testimony,

1326:14–19; Pl.’s Exh. 462 at 7. Barker Testimony, 1752:25–1753:3.

215. Integrated circuits are manufactured on wafers. Each wafer can hold hundreds of

integrated circuits (or die). For purposes of calculating inventory, it is necessary to know

how many die meet standards sufficient to turn them into a finished good and sold to

customers—in other words the yield of a particular wafer. The yield is a percentage

calculated by taking number of good die on a wafer and dividing it by the total number of

die on the wafer. To determine the total number of die produced, the actual number of good

die on each wafer is added together. Barker Testimony, 1754:18–1755:7. 

216. The standard yield for a particular product wafer is based on the actual yields of that

product over a period of time. Standard yields are used to value inventories. Barker

Testimony, 1755:8–12, 1767:11–1768:17–23. 

217. Micrel did not produce the underlying actual yield data (found in its manufacturing

databases) in order that the standard yields it utilized could be independently verified. 

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Barker Testimony, 1767:11–1769:5. Barker admitted that he did not even recall looking for

the actual yield data. Id. at 1774:13–15. Additionally, the documents that Barker relied on

to calculate Micrel’s inventory calculations are not reliable as it is unclear when they were

created. Barker conceded that he did not know the creation date of many of these

documents. Id. at1758:10–1760:25.

218. Further, although Barker asserts that he used information from Micrel’s die database

to calculate inventory, Micrel did not produce all the underlying database information and

LTC did not have an opportunity to inspect any of the records in that database. Barker

Testimony, 1758:8–1760:13.

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