Ex Parte SridharaDownload PDFPatent Trial and Appeal BoardNov 28, 201713567227 (P.T.A.B. Nov. 28, 2017) Copy Citation United States Patent and Trademark Office UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O.Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 13/567,227 08/06/2012 Srinivasa Raghavan Sridhara TI-72495 8980 23494 7590 11/30/2017 TEXAS INSTRUMENTS INCORPORATED P O BOX 655474, M/S 3999 DALLAS, TX 75265 EXAMINER BASHAR, MOHAMMED A ART UNIT PAPER NUMBER 2824 NOTIFICATION DATE DELIVERY MODE 11/30/2017 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): uspto@ti.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte SRINIVASA RAGHAVAN SRIDHARA1 Appeal 2017-003311 Application 13/567,227 Technology Center 2800 Before PETER F. KRATZ, ROMULO H. DELMENDO, and MONTE T. SQUIRE, Administrative Patent Judges. SQUIRE, Administrative Patent Judge. DECISION ON APPEAL2 Appellant appeals the Examiner’s decision finally rejecting claims 1— 8, which constitute all the claims pending in this application. 35 U.S.C. § 134(a). We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM. 1 Appellant identifies Texas Instruments Incorporated as the real party in interest. App. Br. 1. 2 In our Decision, we refer to the Specification filed August 6, 2012 (“Spec.”); Final Office Action dated August 13, 2015 (“Final Act.”); Appeal Brief dated January 4, 2016 (“App. Br.”); and Examiner’s Answer to the Appeal Brief dated July 25, 2016 (“Ans.”). There is no Reply Brief filed in this Appeal. Appeal 2017-003311 Application 13/567,227 The Claimed Invention Appellant’s disclosure relates to a method for testing the retention mode of an array of static random access memory (SRAM) cells. Spec., Abstract, 111, 26. Claim 1 is illustrative of the claimed subject matter on appeal and is reproduced below from the Claims Appendix to the Appeal Brief (App. Br. 8) (key disputed claim language italicized and bolded and indentation added): 1. A method of testing the retention mode of an array of static random access memory (SRAM) cells, comprising: writing a data pattern to the array of SRAM cells, wherein each SRAM cell in the array of SRAM cells has a known value; enabling a retention mode for the array of SRAM cells wherein leakage current from sources internal to the array of SRAM cells draws a first current from a supply line for a period of time; enabling a discharge mode wherein a second current, external to the array of SRAM cells, is drawn from the supply line for the period of time wherein the supply line reaches a first voltage at the end of the period of time; disabling the retention mode and the discharge mode after the period of time has expired wherein the supply line is restored to a second voltage, the second voltage having a higher voltage than the first voltage; reading the data pattern from the array of SRAM cells; and comparing the data pattern read from the array of SRAM cells to the data pattern written to the array of SRAM cells. 2 Appeal 2017-003311 Application 13/567,227 The References The Examiner relies on the following prior art references as evidence in rejecting the claims on appeal: Loh et al., US 7,324,391 B2 Jan. 29, 2008 (hereinafter “Loh”) Nil US 2008/0316837 Al Dec. 25, 2008 The Rejection On appeal, the Examiner maintains the following rejection: claims 1— 8 are rejected under 35 U.S.C. § 103(a) as being unpatentable over Nil in view of Loh. Final Act. 2; Ans. 1. OPINION Having considered the respective positions advanced by the Examiner and Appellant in light of this appeal record, we affirm the Examiner’s rejections based on the fact finding and reasoning set forth in the Answer to the Appeal Brief and Final Office Action, which we adopt as our own. See In re Jung, 637 F.3d 1356, 1365 (Fed. Cir. 2011) (“[I]t has long been the Board’s practice to require an applicant to identify the alleged error in the examiner’s rejections,” citing Ex parte Frye, 94 USPQ2d 1072, 1075 (BPAI 2010) (precedential)). We highlight and address specific findings and arguments below for emphasis. Claims 1—5 Appellant argues claims 1—5 as a group. App. Br. 4—5. We select claim 1 as representative of this group and claims 2—5 stand or fall with claim 1. 37 C.F.R. § 41.37(c)(l)(iv). 3 Appeal 2017-003311 Application 13/567,227 The Examiner determines that the combination of Nil and Loh suggests a method of testing the retention mode of an array of SRAM cells satisfying all of the steps of claim 1 and thus, would have rendered claim 1 obvious. Final Act. 2—3. The Examiner finds that Nil teaches or suggests the majority of the steps of claim 1, but that the reference is “silent about writing and reading data including voltage level with period of time.” Final Act. 2 (citing Nil, Figs. 28-33,11296-298, 307-308, 333-334). The Examiner, however, relies on Foh for suggesting these missing claim steps. Final Act. 2. In particular, the Examiner finds that Foh teaches writing a data pattern to the array of SRAM cells, wherein each SRAM cell in the array of SRAM cells has a known value; reading the data pattern from the array of SRAM cells; and comparing the data pattern read from the array of SRAM cells to the data pattern written to the array of SRAM cells. Id. at 2—3 (citing Foh, Fig. 3, col. 7,11. 15—43). Based on the above findings, the Examiner concludes that: It would have been obvious to one of ordinary skill... at the time of the invention to apply the teaching of Foh et al to the teaching of Nil for the purpose of how common steps of writing and reading data pattern [are] applied in retention test. Further reason to combine the teachings of Foh et al and Nil is evidenced by virtue of their common field of endeavor, e.g. both are drawn towards retention test of SRAM memory. Final Act. 3. Appellant argues that the Examiner’s rejection of claim 1 should be reversed because “Nil fails to teach a discharge mode wherein a second current, external to the array of SRAM cells, is drawn from the supply line for a period of time,” as required by the claim. App. Br. 5. Appellant 4 Appeal 2017-003311 Application 13/567,227 contends that the portions of Nil relied upon by the Examiner for teaching this limitation “discusses leakage current from memory cells internal to the array of SRAM cells; not externally.” Id. at 5. We do not find Appellant’s arguments persuasive of reversible error in the Examiner’s rejection. On the record before us, we find that a preponderance of the evidence and sound technical reasoning support the Examiner’s determination that the combination of Nil and Loh suggests all of the steps of claim 1, including “enabling a discharge mode wherein a second current, external to the array of SRAM cells, is drawn from the supply line for the period of time.” Nil, Figs. 28—33, H 296—298, 307—308, 333-334; Loh, Fig. 3, col. 7,11. 15^13. As the Examiner finds (Ans. 3—5) and Appellant does not dispute, the Nil reference does suggest “enabling a discharge mode wherein a second current, external to the array of SRAM cells, is drawn from the supply line for the period of time.” In particular, relying on Figures 29 and 32 and paragraphs 288, 289, 293—95, and 307 of Nil, the Examiner finds Nil suggests a scenario where both transistors 202 (Fig. 29) and 302 (Fig. 32) would be turned on and when the memory cell of the VDD control circuit (Fig. 29) is accessed, a discharge current—external to the array of SRAM cells—would flow from supply line VM to ground GND (Fig. 32). See also Nil 11308, 333-334. Appellant’s argument does not reveal reversible error in the Examiner’s analysis and factual findings in this regard. The Examiner also provides a reasonable basis and identifies a preponderance of the evidence in the record to evince why one of ordinary skill would have combined the teachings of the references to arrive at 5 Appeal 2017-003311 Application 13/567,227 Appellant’s claimed invention. Final Act. 3 (explaining that it would have been obvious to one of ordinary skill to combine the teachings of Loh and Nil to arrive at the claimed method because writing and reading data patterns in retention tests are “common steps”); see also KSR Int 7 Co. v. Teleflex, Inc., 550 U.S. 398, 416 (2007) (“The combination of familiar elements according to known methods is likely to be obvious when it does no more than yield predictable results.”). Appellant fails to direct us to sufficient evidence or provide an adequate technical explanation to establish why the Examiner’s articulated reasoning for combining the teachings of the prior art to arrive at the claimed invention lacks a rational underpinning or is otherwise based on some other reversible error. Claims 6—8 Appellant additionally argues claims 6—8 as a group. App. Br. 7. We select claim 6 as representative and claims 7 and 8 stand or fall with claim 6. 37 C.F.R. §41.37(c)(l)(iv). Claim 6 is drawn to a circuit for testing retention mode of an array of Static Random Access Memory (SRAM) cells and recites a discharge circuit: wherein during the period of time the discharge circuit draws a third current, external to the array of SRAM cells, from the supply line for the period of time, wherein the voltage on the supply line is a first voltage at the end of the period of time. App. Br. 9-10 (Claims App’x) (emphasis added). Appellant argues that the Examiner’s rejection of claim 6 should be reversed for the same reasons previously presented in response to the Examiner’s rejection of claim 1. App. Br. 6. In particular, Appellant argues 6 Appeal 2017-003311 Application 13/567,227 that “Nil fails to teach a discharge circuit that draws a third current, external to the array of SRAM cells from the supply line for the period of time.” Id. at 6. We do not find Appellant’s argument persuasive of reversible error in the Examiner’s rejection of claim 6 for the same reasons previously discussed above regarding claim 1. Accordingly, we affirm the Examiner’s rejection of claims 1—8 under 35 U.S.C. § 103(a) as obvious over the combination of Nil and Loh. DECISION/ORDER The Examiner’s rejection of claims 1—8 are affirmed. It is ordered that the Examiner’s decision is affirmed. No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a). AFFIRMED 7 Copy with citationCopy as parenthetical citation