Aspects of the present disclosure provide an oscillating circuit. An example oscillating circuitry generally includes a differential control pair comprising a first control node and a second control node. The oscillating circuit further includes a first voltage-controlled oscillator (VCO) comprising a first differential varactor circuit having a first positive control input coupled to the first control node and a first negative control input coupled to the second control node. The oscillating circuit also includes a second differential varactor circuit having a second positive control input coupled to the second control node and a second negative control input coupled to the first control node.

An oscillator circuit includes a core stage having a voltage controlled oscillator arranged to output an output oscillation signal, and an input stage coupled to the output stage via an induction coupling, and arranged to receive an input oscillation signal; wherein the output oscillation signal includes an output oscillation frequency substantially equals to a multiplication of an input oscillation frequency of the input oscillation signal.

A temperature-controlled and temperature-compensated oscillating device and a method of temperature control and temperature compensation is disclosed. The operating temperature of a frequency source is adjusted by driving a heater to a target temperature when the ambient temperature is in a first range between a first temperature and a second temperature higher than the third temperature. The frequency variation of the frequency source resulted from a variation of the ambient temperature is reduced by applying a voltage to the frequency source when the ambient temperature is in a second range between a third temperature and a fourth temperature higher than the third temperature. The third temperature is higher than the first temperature.

An oscillator circuit includes a core stage having a voltage controlled oscillator arranged to output an output oscillation signal, and an input stage coupled to the output stage via an induction coupling, and arranged to receive an input oscillation signal; wherein the output oscillation signal includes an output oscillation frequency substantially equals to a multiplication of an input oscillation frequency of the input oscillation signal.

A semiconductor device according to the present embodiment includes a plurality of switching elements and a plurality of variable capacitance elements. The switching elements are switching elements connected in series between a first control terminal and a second control terminal and plural types of capacitance control signals can be supplied to the first control terminal and the second control terminal. The variable capacitance elements have capacitance control terminals connected to corresponding one ends of the switching elements, respectively.

An oscillator operable in Class-C comprises at least one set of cross-coupled transistors. A threshold voltage of the transistors is controllable by having a bias voltage applied at back-gates of the transistors. The bias voltage thereby controls a conduction angle of the transistors to enable operation of the oscillator in Class-C. There is further provided a radio transceiver comprising such an oscillator, a method of operating such an oscillator, and a controller configured to operate such an oscillator.

The present disclosure relates to an electronic device comprising a first capacitor and a quartz crystal coupled in series between a first node and a second node; an inverter coupled between the first and second nodes; a first variable capacitor coupled between the first node and a third node; and a second variable capacitor coupled between the second node and the third node.

A semiconductor device according to the present embodiment includes a plurality of switching elements and a plurality of variable capacitance elements. The switching elements are switching elements connected in series between a first control terminal and a second control terminal and plural types of capacitance control signals can be supplied to the first control terminal and the second control terminal. The variable capacitance elements have capacitance control terminals connected to corresponding one ends of the switching elements, respectively.

Disclosed herein is a fine capacitance tuning circuit for a digitally controlled oscillator. The tuning circuit has low and high frequency tuning banks formed by varactors that have their top plates connected to one another. A controller initially sets states of switches selectively connecting the bottom plates of the varactors of the low frequency bank to a low voltage, a high voltage, or to an RC filter, in response to an integer portion of a control word. A sigma-delta modulator initially sets the states of switches selectively connecting the bottom plates of the varactors of the high frequency bank to either the low voltage or the high voltage, in response to a fractional portion of the control word. The controller modifies the states of the switches of the tuning banks in a complementary fashion, based upon comparisons between the fractional portion of the control word and a series of thresholds.

An LC oscillator architecture in which an LC tank is driven by a negative resistance element (amplifier) including first and second Vbe/Vgs multipliers cross-coupled to the LC tank. Each Vbe/Vgs multiplier circuitry including a transistor with a control terminal as a negative input, a reference terminal as a positive input, and an output terminal, a shunt resistance connected between the control terminal and the reference terminal, a series resistance connected between the control terminal and the output terminal for one of the same transistor or the other transistor, and a shorting capacitance connected between the control terminal of the transistor, and the output terminal of the transistor of the other Vbe/Vgs multiplier. An example application is an LC VCO, such as for a PLL, CDR, or retimer.