An integrated circuit includes an inverter, first and second capacitors, a resistor, and a transistor. The inverter has an input and an output. The first capacitor is coupled to a ground. The transistor has a first transistor terminal, a second transistor terminal, and a control input. The first transistor terminal is coupled to the first capacitor and the second transistor terminal is coupled to the input of the inverter. The second capacitor is coupled between the output of the inverter and the ground. The resistor is coupled between the output of the inverter and the first transistor terminal.

The present invention relates to an active shunt capacitance cancelling oscillator circuit. Such systems can be used in resonator-based methods, while avoiding impedance distortion and phase shift anomalies.

Examples of increasing yield and operating temperature range of transmitters are disclosed. In one example, a transmitter has an a thin-film bulk acoustic (FBAR) resonator. The transmitter may be a Bluetooth Low Energy (BLE) transmitter. In this example, the FBAR-based BLE transmitter does not require or have a phase locked loop, and does not require or have a crystal reference. The FBAR-based BLE transmitter may have an oscillator with a split capacitor array. The oscillator may be a Pierce oscillator with a split capacitor array. The FBAR-based transmitter and calibration methods described herein provide a greater yield and wider operating range than prior transmitters.

An oscillator includes a crystal oscillation circuit configured to generate an oscillation signal having a natural frequency, an injection circuit configured to inject a first injection signal and a second injection signal into the crystal oscillation circuit, a dithering circuit configured to transmit a first control signal for generating the first injection signal to the injection circuit, and a phased-lock loop (PLL) circuit configured to lock a phase of the first injection signal to the natural frequency, to transmit a second control signal for generating the second injection signal to the injection circuit.

A clock generator can include a Fin Field Effect Transistor (FinFET) oscillator and a phased-locked loop (PLL). The FinFET oscillator can generate a FinFET signal. The PLL can generate an output clock signal based on a reference clock signal and the FinFET signal.

A clock generator can include a Fin Field Effect Transistor (FinFET) oscillator and a phased-locked loop (PLL). The FinFET oscillator can generate a FinFET signal. The PLL can generate an output clock signal based on a reference clock signal and the FinFET signal.

A crystal oscillator and a phase noise reduction method thereof are provided. The crystal oscillator may include a crystal oscillator core circuit, a first bias circuit and a phase noise reduction circuit, the first bias circuit is coupled to an output terminal of the crystal oscillator core circuit, and the phase noise reduction circuit is coupled to the output terminal of the crystal oscillator core circuit. In operations of the crystal oscillator, the crystal oscillator core circuit is configured to generate a sinusoidal wave. The first bias circuit is configured to provide a first voltage level to be a bias voltage of the sinusoidal wave. The phase noise reduction circuit is configured to reset the bias voltage of the sinusoidal wave in response to a voltage level of the sinusoidal wave exceeding a specific voltage range. For example, the specific voltage range is determined according to a second voltage level.

A crystal oscillator and a phase noise reduction method thereof are provided. The crystal oscillator includes a crystal oscillator core circuit, a bias circuit coupled to an output terminal of the crystal oscillator core circuit, a pulse wave buffer coupled to the output terminal of the crystal oscillator core circuit, and a phase noise reduction circuit coupled to the output terminal of the crystal oscillator core circuit. The crystal oscillator core circuit may generate a sinusoidal wave. The bias circuit may provide a bias voltage of the sinusoidal wave. The pulse wave buffer may generate a pulse wave according to the sinusoidal wave. The phase noise reduction circuit may provide an alternating current (AC) ground path for noise on the bias voltage according to a reset pulse, wherein a position of the reset pulse is set by a control voltage on a control terminal of the phase noise reduction circuit.

Both parallel-type and serial-type dual-mode oscillators employing stress compensated cut resonators having various configurations are disclosed. Both classes of dual-mode oscillators employ multiple tank circuits to pass one frequency of the resonator and block the other frequency. The tank circuits isolate the operation of the two oscillator sub-circuits that form the dual-mode oscillator from one another. The dual-mode oscillators may be implemented with either bipolar or CMOS transistors. The parallel-type dual-mode oscillators employ inverters to provide gain. The serial-type dual-mode oscillators employ a two (or three) stage design including a follower circuit first stage and an inverting amplifier/limiter circuit second stage, with an optional intervening transimpedance amplifier stage.

A crystal oscillator and a phase noise reduction method thereof are provided. The crystal oscillator may include a crystal oscillator core circuit, a first bias circuit and a phase noise reduction circuit, the first bias circuit is coupled to an output terminal of the crystal oscillator core circuit, and the phase noise reduction circuit is coupled to the output terminal of the crystal oscillator core circuit. In operations of the crystal oscillator, the crystal oscillator core circuit is configured to generate a sinusoidal wave. The first bias circuit is configured to provide a first voltage level to be a bias voltage of the sinusoidal wave. The phase noise reduction circuit is configured to reset the bias voltage of the sinusoidal wave in response to a voltage level of the sinusoidal wave exceeding a specific voltage range.