# US 2013/0157594 A1 · Circuits and methods for increasing output frequency of an lc oscillator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0157594 A1 - Document ID: US20130157594A1 - Status: Published application - Kind: A1 - Application number: 13/715,018 - Filed: 2012-12-14 - Published: 2013-06-20 - Earliest claimed: 2011-12-16 - Assignees: Skyworks Solutions, Inc. - Inventors: Georgi Milev Taskov - Web page: https://patentgrep.com/patent/US20130157594A1 ## CPC - H03B 5/1215: {the current source or degeneration circuit being in common to both transistors of the pair, e.g. a cross-coupled long-tailed pair} - B23K 31/02: relating to soldering or welding - H03B 5/1212: {the amplifier comprising a pair of transistors, wherein an output terminal of each being connected to an input terminal of the other, e.g. a cross coupled pair} - H03B 5/1228: {the amplifier comprising one or more field effect transistors} - H03H 7/0115: {comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence)} - H04B 1/0458: {Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages (matching circuits in general H03H)} - H04B 1/18: Input circuits, e.g. for coupling to an antenna or a transmission line (coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H) - H04B 1/403: using the same oscillator for generating both the transmitter frequency and the receiver local oscillator frequency - H10W 72/075: {of bond wires} - H03B 2200/0026: relating to the pins of integrated circuits - H03B 2200/0036: including an emitter or source coupled transistor pair or a long tail pair - H04W 88/02: Terminal devices - H10W 72/5445: {being orthogonal to a side surface of the chip, e.g. parallel arrangements} - H10W 72/5453: {connecting between multiple bond pads on a chip, e.g. daisy chain} - H10W 72/5522: {comprising gold [Au]} - H10W 72/932: {Plan-view shape, i.e. in top view} - H10W 90/754: {between a chip and a stacked insulating package substrate, interposer or RDL} - Y10T 29/4902: Electromagnet, transformer or inductor - H03B: GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (generators adapted for electrophonic musical instruments G10H; masers or lasers H01S; generation of oscillations in plasma H05H) - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - H04B: TRANSMISSION - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Disclosed are circuits and methods for increasing an output frequency of an inductance-capacitance (LC) oscillator. In some embodiments, the LC oscillator can be implemented as a voltage-controlled oscillator (VCO) having differential outputs. When the VCO is implemented on a die, wirebond connections from the outputs to a ground results in an effective inductance that impacts a maximum frequency associated with the VCO. An electrical connection such as a wirebond between the differential outputs yields a reduction in the effective inductance thereby increasing the maximum frequency. In some embodiments, the wirebond between the differential outputs can be configured so that its contribution to mutual inductance is reduced or substantially nil. ## Claims ### Claim 1 A radio-frequency (RF) module comprising: a packaging substrate configured to receive a plurality of components, the packaging substrate further configured to receive and connect a plurality of wirebonds to a common electrical potential; a die mounted on the substrate, the die including an oscillator circuit that includes differential outputs, the die further including first and second bond pads electrically connected to the differential outputs; a first wirebond that connects the first bond pad with the common electrical potential of the packaging substrate, the first wirebond having an inductance of L1; a second wirebond that connects the second bond pad with the common electrical potential of the packaging substrate, the second wirebond having an inductance of L2, the first and second wirebonds being electrically parallel; a third wirebond that electrically connects the first and second bond pads, the third wirebond having an inductance of L3, the first, second and third wirebonds in combination having an inductance L″ that is lower than an inductance L′ corresponding to a combination of L1 and L2 without L3. ### Claim 2 (depends on 1) The module of claim 1 wherein the first and second wirebonds define respective first and second planes that are approximately parallel to each other. ### Claim 3 (depends on 2) The module of claim 2 wherein the third wirebond defines a third plane that is approximately perpendicular to each of the first and second planes so as to yield a reduced mutual inductance between the third wirebond and the parallel first and second wirebonds. ### Claim 4 (depends on 3) The module of claim 3 wherein the first, second and third wirebonds are configured to yield an approximate electrical symmetry between the first and second bond pads, such that the third wirebond can be represented by two inductances in series with an AC ground in between, each of the two inductances having a value of approximately half of L3. ### Claim 5 (depends on 4) The module of claim 4 wherein each of L1, L2 and L3 has a value of approximately equal to that of L, such that L″ is approximately equal to L/3. ### Claim 6 (depends on 1) The module of claim 1 wherein the reduced inductance L″ yields an increase in a maximum frequency of the oscillator by a multiplicative factor as large as about sqrt(3) compared to a maximum frequency without the third wirebond. ### Claim 7 (depends on 6) The module of claim 6 wherein the reduced inductance L″ allows a proportional increase in capacitance C for a given frequency of oscillation represented as 1/Sqrt(L″*C)) thereby providing phase noise improvement proportional to a reduction in L″ and an increase in C. ### Claim 8 (depends on 1) The module of claim 1 wherein the third wirebond having both of its ends positioned on the die results in L3 being substantially unaffected by variations in placement of the die on the substrate. ### Claim 9 (depends on 1) The module of claim 1 wherein the common electrical potential includes a ground potential. ### Claim 10 (depends on 1) The module of claim 1 wherein the oscillator is a voltage controlled oscillator (VCO). ### Claim 11 (depends on 10) The module of claim 10 wherein VCO is part of a frequency synthesizer circuit formed on the die. ### Claim 12 (depends on 1) The module of claim 1 wherein each of the first, second and third wirebonds includes gold. ### Claim 13 A portable wireless device comprising: an antenna configured to receive a radio-frequency (RF) signal; a receiver circuit connected to the antenna and configured to process the received RF signal; and a voltage controlled oscillator (VCO) circuit coupled to and configured to facilitate operation of the receiver circuit, the VCO having differential outputs through first and second electrically parallel conductors and a third conductor configured to electrically connect the differential outputs, the first, second and third conductors in combination having an inductance that is lower than an inductance corresponding to a combination of the first and second conductors without the third conductor, the lowered inductance yielding an increase in a maximum frequency of the VCO circuit. ### Claim 14 (depends on 13) The wireless device of claim 13 further comprising a transmitter circuit configured to generate an RF signal to be translated, the VCO being further coupled to and configured to facilitate operation of the transmitter circuit. ### Claim 15 (depends on 14) The wireless device of claim 14 wherein the antenna is further connected to the transmitter circuit and configured to transmit the RF signal generated by the transmitter circuit. ### Claim 16 (depends on 15) The wireless device of claim 15 wherein the wireless device is a cellular phone. ### Claim 17 A method for fabricating a VCO based device, the method comprising: providing an LC oscillator circuit having differential outputs; forming a conductive path between each of the differential outputs and a ground; and forming a conductive path between the differential outputs such that the first, second and third conductive paths in combination yields an inductance that is lower than an inductance corresponding to a combination of the first and second conductive paths without the third conductive path, the lowered inductance yielding an increase in a maximum frequency of the LC oscillator circuit. ### Claim 18 (depends on 17) The method of claim 17 further comprising mounting the LC oscillator circuit on a packaging substrate. ### Claim 19 (depends on 18) The method of claim 18 wherein the LC oscillator circuit and the differential outputs are formed on a die, and the ground is part of the packaging substrate. ### Claim 20 (depends on 19) The method of claim 19 wherein each of the first, second and third conductive paths includes a wirebond.