Abstract: A TPoS resonator includes a substrate and a resonator body suspended over the substrate by at least a first pair of fixed supports (e.g., tethers) that attach to first and second ends of the resonator body. The resonator body includes monocrystalline silicon, which has a [100] crystallographic orientation that is offset by ±? degrees relative to a nodal line of the resonator body (e.g., tether-to-tether axis) when the resonator body is operating at a resonant frequency, where a is a real number in a range from about 5 to about 19 and, more preferably, in a range from about 7 to about 17. The resonator may be an extensional-mode resonator and the resonator body may be rectangular-shaped with unequal length and width dimensions.

Abstract: Integrated circuit devices include a packaged MEMS-based oscillator circuit, which is configured to support bidirectional frequency margining of a periodic output signal. This bidirectional frequency margining is achieved using a first signal to synchronize changes in a frequency of the periodic output signal and a second signal to control whether the changes in the frequency of the periodic output signal are incremental or decremental. In particular, the oscillator circuit may be configured so that each change in the frequency of the periodic output signal is synchronized to a corresponding first voltage transition of the first signal and a voltage level of the second signal may be used to control whether the changes in the frequency of the periodic output signal are incremental or decremental.

Abstract: Integrated circuit devices may utilize automatic methods for adjusting the tail currents of current mode logic (CML) cells, which compensate for variations in process corners and thereby enable reliable operation of high performance circuits, such as frequency synthesizers. An integrated circuit may include a current mode logic (CML) circuit responsive to at least one input signal and a variable current source electrically coupled to the CML circuit. This variable current source can be configured to sink (or source) a first current from (or to) the CML circuit in response to a control signal. A control circuit may also be provided, which is configured to generate the control signal in response to a process corner indication signal. This process corner indication signal, which may be generated by a process corner detection circuit, preferably has a magnitude that estimates a relative speed of a process corner associated with the integrated circuit device.

Abstract: Oscillator circuits include a MEMs resonator, a variable impedance circuit (e.g., varistor) and an adjustable gain amplifier. The variable impedance circuit includes a first terminal electrically coupled to a first terminal of the MEMs resonator and the adjustable gain amplifier is electrically coupled to the variable impedance circuit. The adjustable gain amplifier may have an input terminal electrically coupled to the variable impedance circuit and a second terminal of the MEMs resonator may receive, as feedback, a signal derived from an output of the adjustable gain amplifier. A Q-factor control circuit may be provided, which is configured to drive the variable impedance circuit and the adjustable gain amplifier with first and second control signals, respectively, that cause an impedance of the variable impedance circuit and a gain of the adjustable gain amplifier to be relatively high during a start-up time interval and relatively low during a post start-up time interval.

Abstract: A periodic signal generator is configured to generate high frequency signals characterized by relatively low temperature coefficients of frequency (TCF). A microelectromechanical resonator, such as concave bulk acoustic resonator (CBAR) supporting capacitive and piezoelectric transduction, may be geometrically engineered as a signal generator that produces two periodic signals having unequal resonant frequencies with unequal temperature coefficients. Circuitry is also provided for combining the two periodic signals using a mixer to thereby yield a high frequency low-TCF periodic difference signal at an output of the periodic signal generator.

Abstract: A microelectromechanical resonator includes a resonator body, which is encapsulated within a sealed cavity extending between first and second substrates that are bonded together. The resonator body is anchored to the first substrate by at least a pair of tethers that suspend the resonator body opposite an underlying recess in the first substrate. A resistive heating element is provided, which is configured to indirectly heat the resonator body through convective heating of the cavity. This resistive heating element may be disposed on an inner surface of the second substrate that is exposed to the cavity. The resonator may also include first and second electrical interconnects, which extend through the second substrate and contact respective first and second portions of the resistive heating element.

Abstract: A frequency synthesizer includes a frequency generator configured to generate a periodic output signal in response to a periodic input signal and a temperature-dependent code. A temperature sensor is provided, which is configured to generate a temperature measurement signal in response to detecting a temperature of at least a portion of the frequency synthesizer. A control circuit is provided, which is configured to generate the temperature-dependent code in response to the temperature measurement signal and a plurality of clocks having unequal frequencies. The control circuit can include a cascaded arrangement of an oversampled data converter and a digital filter, which are sequentially responsive to first and second ones of the plurality of clocks during generation of the periodic output signal by the frequency generator.

Abstract: Microelectromechanical resonators include a resonator body with a built-in piezoelectric-based varactor diode. This built-in varactor diode supports passive frequency tuning by enabling low-power manipulation of the stiffness of a piezoelectric layer, in response to controlling charge build-up therein at resonance. A resonator may include a composite stack of a bottom electrode, a piezoelectric layer on the bottom electrode and at least one top electrode on the piezoelectric layer. The piezoelectric layer includes a built-in varactor diode, which is defined by at least two regions having different concentrations of electrically active dopants therein.

Abstract: A frequency synthesizer is configured to generate a periodic output signal in response to a periodic input signal and a temperature-dependent frequency adjusting control signal. A temperature sensor is provided, which is configured to generate a temperature measurement signal in response to detecting a temperature of at least a portion of the frequency synthesizer. A control circuit is provided, which is configured to generate the temperature-dependent frequency adjusting control signal in response to the temperature measurement signal. This control circuit includes a cascaded arrangement of an oversampled data converter and a multi-stage digital filter, which is configured to generate a plurality of codes from respective ones of the digital filter stages, and a selection circuit, which is configured to use at least first and second ones of the plurality of codes in sequence during first and second consecutive time intervals to generate the temperature-dependent frequency adjusting control signal.

Abstract: Methods of forming substrates having two-sided microstructures therein include selectively etching a first surface of the substrate to define a plurality of alignment keys therein that extend through the substrate to a second surface thereof. A direct photolithographic alignment step is then performed on a second surface of the substrate by aligning a photolithography mask to the plurality of alignment keys at the second surface. This direct alignment step is performed during steps to photolithographically define patterns in the second surface.

Abstract: Micro-electromechanical acoustic resonators include a substrate having a cavity therein and a resonator body suspended over the cavity. The resonator body is anchored on opposing sides thereof (by support beams) to first and second portions of the substrate. These first and second portions of the substrate, which extend over the cavity as first and second ledges, respectively, each have at least one perforation therein disposed over the cavity. These perforations may be open or filled. The first and second ledges are formed of a first material (e.g., silicon) and the first and second ledges are filled with a second material having a relatively high acoustic impedance relative to the first material. This second material may include a material selected from a group consisting of tungsten (W), copper (Cu), molybdenum (Mo).

Abstract: Methods of forming packaged micro-electromechanical devices include forming a first substrate having a micro-electromechanical device therein, which extends adjacent a first surface of the first substrate. A first surface of a second substrate is then bonded to the first surface of the first substrate, to thereby encapsulate the micro-electromechanical device within a space provided between the first and second substrates. Subsequent to bonding, a second surface of the second substrate is selectively etched to define at least one through-substrate opening therein, which exposes an electrode of the micro-electromechanical device. Thereafter, the through-substrate opening is filled with an electrically conductive through-substrate via.

Abstract: Micro-electromechanical acoustic resonators include a resonator body suspended over a substrate. The resonator body may have a single perforation therein, which may extend substantially or completely therethrough. The resonator body may also be configured to have a center-of-mass within an interior of the perforation and/or a nodal line that overlaps the perforation. A perimeter and depth of the single perforation can be configured to reduce a susceptibility of the acoustic resonator to process-induced variations in resonant frequency relative to an otherwise equivalent resonator that omits the single perforation. In other embodiments, the resonator body may have multiple perforations therein that extend along a nodal line of the resonator.

Abstract: Methods of forming multi-chip semiconductor substrates include forming a first plurality of dicing streets in a first surface of a first semiconductor wafer having a first plurality of bonding sites thereon and forming a second plurality of dicing streets in a first surface of a second semiconductor wafer having a second plurality of bonding sites thereon. The first surfaces of the first and second semiconductor wafers are bonded together so that the first plurality of dicing streets are aligned with the second plurality of dicing streets and the first plurality of bonding sites are matingly received and permanently affixed within the second plurality of bonding sites. A plurality of bonded pairs of semiconductor chips are then formed by planarizing the second surface of the second semiconductor wafer until the second plurality of dicing streets are exposed.

Abstract: Micro-electromechanical devices include a temperature-compensation capacitor and a thin-film bulk acoustic resonator having a first terminal electrically coupled to an electrode of the temperature-compensation capacitor. The temperature-compensation capacitor includes a bimorph beam having a first electrode thereon and a second electrode extending opposite the first electrode. This bimorph beam is configured to yield an increase in spacing between the first and second electrodes in response to an increase in temperature of the micro-electromechanical device. This increase in spacing between the first and second electrodes leads to a decrease in capacitance of the temperature-compensation capacitor. Advantageously, this decrease in capacitance can be used to counteract a negative temperature coefficient of frequency associated with the thin-film bulk acoustic resonator, and thereby render the resonant frequency of the micro-electromechanical device more stable in response to temperature fluctuations.

Abstract: Micro-electromechanical devices include a temperature-compensation capacitor and a thin-film bulk acoustic resonator having a first terminal electrically coupled to an electrode of the temperature-compensation capacitor. The temperature-compensation capacitor includes a bimorph beam having a first electrode thereon and a second electrode extending opposite the first electrode. This bimorph beam is configured to yield an increase in spacing between the first and second electrodes in response to an increase in temperature of the micro-electromechanical device. This increase in spacing between the first and second electrodes leads to a decrease in capacitance of the temperature-compensation capacitor. Advantageously, this decrease in capacitance can be used to counteract a negative temperature coefficient of frequency associated with the thin-film bulk acoustic resonator, and thereby render the resonant frequency of the micro-electromechanical device more stable in response to temperature fluctuations.

Abstract: Thin-film bulk acoustic resonators include a resonator body (e.g., silicon body), a bottom electrode on the resonator body and a piezoelectric layer on the bottom electrode. At least one top electrode is also provided on the piezoelectric layer. In order to inhibit process-induced variations in material layer thicknesses from significantly affecting a desired resonant frequency of the resonator, the top and bottom electrodes are fabricated to have a combined thickness that is proportional to a target thickness of the piezoelectric layer extending between the top and bottom electrodes.

Abstract: Micro-electromechanical acoustic resonators include a resonator body suspended over a substrate. The resonator body may have a single perforation therein, which may extend substantially or completely therethrough. The resonator body may also be configured to have a center-of-mass within an interior of the perforation and/or a nodal line that overlaps the perforation. A perimeter and depth of the single perforation can be configured to reduce a susceptibility of the acoustic resonator to process-induced variations in resonant frequency relative to an otherwise equivalent resonator that omits the single perforation. In other embodiments, the resonator body may have multiple perforations therein that extend along a nodal line of the resonator.

Abstract: A baseband processor includes a processing switch for performing orthogonal frequency division multiplexing operations on data packets and routing the data packets in the baseband processor. Additionally, the baseband processor includes digital signal processors for performing symbol processing operations on the data packets. The baseband processor is scalable such that digital signal processors may be added to, or removed from, the baseband processor. Further, the baseband processor is programmable such that the symbol processing operations may be distributed among the digital signal processors.

Abstract: CAM-based search engines may be configured to support multiple databases within a CAM core. These databases may represent tables for different applications, which can be searched sequentially in response to a single indirect instruction that is loaded during a control cycle. The databases to be searched may be identified by a multi-database search instruction that is loaded during a single data cycle, which may overlap with the control cycle. In some cases, the databases may be searched using variations of a primary search key, so that it is unnecessary to repeatedly load the entire search key across a network interface for each search operation within a respective database. Instead, shorter replacement key segments may be loaded for each of a plurality of the search operations and these replacement key segments may be combined with one or more segments of the primary search key in the CAM core to define a desired search key for a respective search operation.