An integrated circuit includes a semiconductor substrate, a metal layer, an inductor in the metal layer, and a shield above the inductor. The metal layer is a first metal layer; and the shield may be is in a second metal layer above the first metal layer. The shield may include a plurality of metal strips substantially perpendicular to metal lines of the inductor.

A system and method include a non-linear dynamic sensor, such as a magnetic field sensor, having an oscillator with a dynamic response that passes through a critical point beyond which the oscillator responds in an oscillatory regime. A processor operatively connected to the non-linear dynamic sensor is configured to, based upon an input signal x received by the non-linear dynamic sensor, adaptively self-tune the non-linear dynamic sensor to a dynamic range within the oscillatory regime adjacent to the critical point such that the input signal x spans the entire dynamic range. An array of such sensors includes a global feedback capability to mitigate coupling losses.

The present disclosure describes a low-power, low-phase-noise (LPLPN) oscillator. The LPLPN oscillator includes a resonator load, an amplifier stage, and a loop gain control circuit. The resonator load is structured to resonate at a primary resonant frequency. The amplifier stage is coupled with the resonator load to develop a loop gain that peaks at the primary resonant frequency. The loop gain control circuit is coupled with the amplifier stage, and it is structured to regulate the loop gain for facilitating the amplifier stage to generate an oscillation signal at the primary resonant frequency and suppress a noise signal at a parasitic parallel resonant frequency (PPRF).

An aspect of the present disclosure concerns an oscillator circuit including a driver circuit that includes a first amplifier and a current detector where the first amplifier produces an oscillation voltage signal, where the current detector detects an oscillation current signal and produces a drive voltage signal, and where the oscillation current signal corresponds to difference in voltage between the oscillation voltage signal and the drive voltage signal; a feedback circuit that includes a second amplifier receiving the oscillation voltage signal and the drive voltage signal, to produce a feedback voltage signal to the driver circuit; and an oscillator that oscillates at a frequency determined in accordance with the drive voltage signal.

A clock oscillator includes with a pullable BAW oscillator to generate an output signal with a target frequency. The BAW oscillator is based on a BAW resonator and voltage-controlled variable load capacitance, responsive to a capacitance control signal to provide a selectable load capacitance. An oscillator driver (such as a differential negative gm transconductance amplifier), is coupled to the BAW oscillator to provide an oscillation drive signal. The BAW oscillator is responsive to the oscillation drive signal to generate the output signal with a frequency based on the selectable load capacitance. The oscillator driver can include a bandpass filter network with a resonance frequency substantially at the target frequency.

A digital phase-locked loop (DPLL) includes a time-to-digital converter (TDC) having a first clock input, a second clock input, and a TDC output. The DPLL includes a digital loop filter (DLF). The DLF output controls a numerically-controlled bulk acoustic wave oscillator (NCBO). The NCBO output is divided down a fractional-N divider and is fed back to the TDC. The NCBO includes a reference oscillator, a phase and/or frequency detector, a charge pump, a loop filter, a voltage-controlled bulk acoustic wave oscillator (VCBO) and a feedback fractional-N divider that has a numerical control input, which is controlled by DLF output of DPLL. The NCBO forms a stable feedback loop and have a loop bandwidth much wider than DPLL loop bandwidth. In steady state, the NCBO output frequency can be linearly numerically adjusted. An auxiliary PLL or a fractional output divider can be used to generate additional needed frequencies.

A resonator oscillator that may be included in a gas sensing system may include an oscillator that may be electrically connected to an external resonator through a conductive line. The oscillator may generate an oscillating signal having a frequency corresponding to a resonance frequency of the external resonator in an oscillating path. A spurious resonance removal circuit on the oscillating path may remove spurious resonance caused by the conductive line from the oscillating path. A gas sensing system may include the oscillator, a resonator that includes a sensor configured to sense a gas, and a frequency counting logic that receives the oscillating signal and a reference clock signal, performs a counting operation on the oscillating signal according to a logic state of the reference clock signal to generate a counted value, and generate a gas sensing output indicating a sensed gas based on the counted value.

An oscillator includes an external terminal, a resonator, and an oscillation circuit that oscillates the resonator. The oscillation circuit includes an amplification circuit and a current source that supplies a current to the amplification circuit, and the current is variably set according to a control signal input from the external terminal.

A stacked-die oscillator package includes an oscillator circuit die having inner bond pads, and outer bond pads, and a bulk acoustic wave (BAW) resonator die having a piezoelectric transducer with a first and second BAW bond pad on a same side coupled to a top and bottom electrode layer across a piezoelectric layer. A first metal bump is on the first BAW bond pad and a second metal bump is on the second BAW bond pad flip chip bonded to the inner bond pads of the oscillator circuit die. A polymer material is in a portion of a gap between the BAW and oscillator circuit die.

An apparatus includes a film bulk acoustic resonator and a field effect transistor. The film bulk acoustic resonator includes first and second electrodes separated by a piezoelectric material. The piezoelectric material is configured such that the application of a potential difference between the first and second electrodes enables the generation of an acoustic wave and associated surface charge in the piezoelectric material. The field effect transistor includes a channel, and source and drain electrodes configured to enable a flow of electrical current through the channel when a potential difference is applied between the source and drain electrodes. The surface charge generated in the piezoelectric material induces a corresponding charge in the first electrode causing a variation in the electrical current flowing through the channel via a portion of the first electrode, the variation in electrical current producing an output signal having a frequency corresponding to that of the acoustic wave.