Prosecution Insights
Last updated: April 19, 2026
Application No. 19/034,947

BACK GATE BIASING OF CRYSTAL OSCILLATORS FOR ENHANCED NEGATIVE RESISTANCE

Non-Final OA §102§103
Filed
Jan 23, 2025
Examiner
SHIN, JEFFREY M
Art Unit
2849
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Skyworks Solutions Inc.
OA Round
1 (Non-Final)
85%
Grant Probability
Favorable
1-2
OA Rounds
2y 2m
To Grant
95%
With Interview

Examiner Intelligence

Grants 85% — above average
85%
Career Allow Rate
826 granted / 968 resolved
+17.3% vs TC avg
Moderate +10% lift
Without
With
+9.5%
Interview Lift
resolved cases with interview
Typical timeline
2y 2m
Avg Prosecution
16 currently pending
Career history
984
Total Applications
across all art units

Statute-Specific Performance

§101
1.2%
-38.8% vs TC avg
§103
45.9%
+5.9% vs TC avg
§102
28.1%
-11.9% vs TC avg
§112
11.4%
-28.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 968 resolved cases

Office Action

§102 §103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claim Rejections - 35 USC § 102 The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. Claim(s) 1-3, 10, and 12-14 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Calhoun et al (Pub 2015/0214894, further referred to as Calhoun). As to claim 1, Calhoun teaches a crystal oscillator (fig 1-3) comprising: a crystal (106, paragraph 27); an inverter (301, paragraphs 2932 and 33) having an input connected to a first terminal of the crystal (XI) and an output connected to a second terminal (Xo) of the crystal, the inverter including an n-type metal oxide semiconductor transistor (301 has an NMOS) and a p-type metal oxide semiconductor transistor (301 has a PMOS) configured to invert an input oscillation signal from the crystal (paragraph 27); and a back gate bias control circuit (202/303) configured to adjust a negative resistance of the inverter (paragraphs 29 and 32) by controlling a body bias (paragraphs 32 and 33, changing the negative resistance is body biasing the transistor) of at least one of the n-type metal oxide semiconductor transistors or the p-type metal oxide semiconductor transistor. As to claim 2, Calhoun teaches controls a body bias of both the n-type metal oxide semiconductor transistor and the p-type metal oxide semiconductor transistor (fig 3, control signal is sent to both transistors). As to claim 3, Calhoun teaches wherein the back gate bias control circuit sets the back gate bias to a first level during startup of the crystal oscillator and to a second level during steady state operation of the crystal oscillator (fig 13, paragraph 46). As to claim 10, Calhoun wherein a source of the p-type metal oxide semiconductor transistor is connected to a reference voltage, a gate of the p-type metal oxide semiconductor transistor is connected to an input of the inverter, a drain of the p-type metal oxide semiconductor transistor is connected to an output of the inverter, a source of the n-type metal oxide semiconductor transistor is connected to a ground voltage, a gate of the n-type metal oxide semiconductor transistor is connected to the input of the inverter, and a drain of the n-type metal oxide semiconductor transistor is connected to the output of the inverter (fig 3, the inverter is formed as standard CMOS inverter between a reference voltage and ground). As to claim 12, Calhoun teaches a method of generating an oscillation signal using a crystal oscillator (fig 1-3) comprising: Receiving an input oscillation signal from a crystal (106, paragraph 27) as an input to an inverter; inverting using an inverter (301, paragraphs 2932 and 33) having an input connected to a first terminal of the crystal (XI) and an output connected to a second terminal (Xo) of the crystal, the inverter including an n-type metal oxide semiconductor transistor (301 has an NMOS) and a p-type metal oxide semiconductor transistor (301 has a PMOS) configured to invert an input oscillation signal from the crystal (paragraph 27); and adjusting a negative resistance of the inverter ((202/303) paragraphs 29 and 32) by controlling a body bias (paragraphs 32 and 33, changing the negative resistance is body biasing the transistor) of at least one of the n-type metal oxide semiconductor transistors or the p-type metal oxide semiconductor transistor. As to claim 13, Calhoun teaches controls a body bias of both the n-type metal oxide semiconductor transistor and the p-type metal oxide semiconductor transistor (fig 3, control signal is sent to both transistors). As to claim 14, Calhoun teaches wherein the back gate bias control circuit sets the back gate bias to a first level during startup of the crystal oscillator and to a second level during steady state operation of the crystal oscillator (fig 13, paragraph 46). Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claim(s) 17-19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Calhoun. As to claim 17, Calhoun teaches a crystal oscillator (fig 1-3) comprising: a crystal (106, paragraph 27); an inverter (301, paragraphs 2932 and 33) having an input connected to a first terminal of the crystal (XI) and an output connected to a second terminal (Xo) of the crystal, the inverter including an n-type metal oxide semiconductor transistor (301 has an NMOS) and a p-type metal oxide semiconductor transistor (301 has a PMOS) configured to invert an input oscillation signal from the crystal (paragraph 27); and a back gate bias control circuit (202/303) configured to adjust a negative resistance of the inverter (paragraphs 29 and 32) by controlling a body bias (paragraphs 32 and 33, changing the negative resistance is body biasing the transistor) of at least one of the n-type metal oxide semiconductor transistors or the p-type metal oxide semiconductor transistor. Calhoun does not explicitly teach using a phase locked loop with the crystal oscillator. As would have been recognized by a person of ordinary skill in the art using a phase locked loop with a crystal oscillator is done merely as intended use with user desired circuitry (crystal oscillators are notoriously well known in the art for generating reference signals and used with PLL circuits). As such it would have been obvious to a person of ordinary skill in the art before the filing date of the invention to use the crystal oscillator taught in Calhoun with a PLL as doing so would be mere matter of intended use to use the crystal oscillator with user desired circuitry. As to claim 18, Calhoun teaches controls a body bias of both the n-type metal oxide semiconductor transistor and the p-type metal oxide semiconductor transistor (fig 3, control signal is sent to both transistors). As to claim 19, Calhoun teaches wherein the back gate bias control circuit sets the back gate bias to a first level during startup of the crystal oscillator and to a second level during steady state operation of the crystal oscillator (fig 13, paragraph 46). Allowable Subject Matter Claims 4-9, 11, 15, 16, 20 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. None of the cited prior art teach or suggest a first controllable source and first body resistor as is recited in claims 4-7; the reference voltage further adjusting the negative resistance as is recited in claims 8, 9, 15-16 and 20; and the first and second feedback resistors with switching recited in claim 11. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Ahmed (Pub 2020/0204115) teaches a body biasing to a transistor of an amplifier in a crystal oscillator. Nasu (Pub 2010/0482094) teaches generating a gate biasing to a inverter amplifier of a crystal oscillator. Any inquiry concerning this communication or earlier communications from the examiner should be directed to JEFFREY M SHIN whose telephone number is (571)270-7356. The examiner can normally be reached M-F 9am-6pm PST. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Menatoallah Youssef can be reached at 571-270-3684. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /JEFFREY M SHIN/Primary Examiner, Art Unit 2849
Read full office action

Prosecution Timeline

Jan 23, 2025
Application Filed
Dec 30, 2025
Non-Final Rejection — §102, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
85%
Grant Probability
95%
With Interview (+9.5%)
2y 2m
Median Time to Grant
Low
PTA Risk
Based on 968 resolved cases by this examiner. Grant probability derived from career allow rate.

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