An oscillator configured to generate an oscillation signal is provided. The oscillator includes a transistor pair and a cross-coupled transistor pair. The transistor pair is coupled to a first current source and has a first transconductance. The first transconductance is changed in response to a current value of the first current source. The cross-coupled transistor pair is coupled to a second current source and has a second transconductance. The second transconductance is changed in response to a current value of second current source. The transistor pair and the cross-coupled transistor pair are mutually coupled by a plurality of inductors. A frequency of the oscillation signal is determined according to the first transconductance and the second transconductance. Furthermore, a clock generator and a method for generating a clock signal thereof are also provided.

A voltage controlled oscillator comprises a negative resistance, a first inductor, a fixed capacitor, and a frequency control component. The frequency control component comprises at least one varactor and at least a second inductor connected in series with the at least one varactor. A magnitude of an inductance of the second inductor is selected such that the frequency control component has an effective capacitance range larger than a capacitance range of the at least one varactor.

A four-phase oscillator includes, a first oscillator configured to output a first differential signal, a second oscillator configured to output a second differential signal shifted in phase with respect to the first differential signal by 90 or 90 degrees, and a control circuit. The first oscillator includes a first tail current source and a second tail current source. The second oscillator includes a third tail current source and a fourth tail current source. The control circuit changes the frequency of the first and second differential signals by controlling at least one of a difference between a first current value supplied from the first tail current source and a third current value supplied from the third tail current source and a difference between a second current value supplied from the second tail current source and a fourth current value supplied from the fourth tail current source.

A system includes a voltage controlled oscillator (VCO) having an adjustable amplitude. The amplitude of the VCO may be adjusted by adjusting voltage level present at a center tap node of an inductor. The VCO may have an adjustable amplitude that may be programmed on a chip-by-chip basis based on a chip parameter, power consumption, or oscillator performance.

A voltage controlled oscillator includes a variable capacitance circuit having a plurality of variable capacitance elements, each having a capacitance that is a function of a tuning voltage, two or more oscillator core circuits, each operable over a specified frequency band, and inductive elements connected between the variable capacitance circuit and the oscillator core circuits.

A voltage controlled oscillator comprises a negative resistance, a first inductor, a fixed capacitor, and a frequency control component. The frequency control component comprises at least one varactor and at least a second inductor connected in series with the at least one varactor. A magnitude of an inductance of the second inductor is selected such that the frequency control component has an effective capacitance range larger than a capacitance range of the at least one varactor.

Aspects of this disclosure relate to a first die includes an LC resonant circuit including a first capacitive element, such as a capacitor or a varactor, and an inductive element. The LC resonant circuit is configured to generate a signal having a frequency of oscillation. The first die includes bump pads electrically coupled to both ends of the first capacitive element. A second die can be flip chip mounted on the first die. Bumps can electrically connect a second capacitive element of the second die in parallel with the first capacitive element of the first die. This can increase the Q factor of the LC resonant circuit.

An oscillator configured to generate an oscillation signal is provided. The oscillator includes a transistor pair and a cross-coupled transistor pair. The transistor pair is coupled to a first current source and has a first transconductance. The first transconductance is changed in response to a current value of the first current source. The cross-coupled transistor pair is coupled to a second current source and has a second transconductance. The second transconductance is changed in response to a current value of second current source. The transistor pair and the cross-coupled transistor pair are mutually coupled by a plurality of inductors. A frequency of the oscillation signal is determined according to the first transconductance and the second transconductance. Furthermore, a clock generator and a method for generating a clock signal thereof are also provided.

A system includes a voltage controlled oscillator (VCO) having an adjustable amplitude. The amplitude of the VCO may be adjusted by adjusting voltage level present at a center tap node of an inductor. The VCO may have an adjustable amplitude that may be programmed on a chip-by-chip basis based on a chip parameter, power consumption, or oscillator performance.

Methods, apparatuses, and systems for providing a variable output using an array of cells are discussed. In the fine tuning bank of an apparatus, control is implemented by selecting a boundary cell from the array of cells and having every cell before the boundary cell in a circuit path be grounded and having the boundary cell and every cell after the boundary cell in the circuit path be connected to a voltage source. The circuit path may be the one formed by using thermometer coding in the fine tuning bank.