Techniques are described that enables controlling the TNULL characteristic of a self-compensated oscillator by controlling the magnitude and direction of the frequency deviation versus temperature, and thus, compensating the frequency deviation.

Techniques are described for staggered-bias varactors. For example, a staggered-bias varactor can include a control voltage node, a number of bias voltage nodes, and a number of sub-varactors coupled in parallel. The control voltage node can be configured to receive a single, variable control voltage; and the bias voltage nodes can each be configured to receive a different, fixed bias voltage. Each sub-varactor is configured, so that its equivalent capacitance is a function of a difference between the control voltage and a respective one of the bias voltages; and the equivalent capacitance of the staggered-bias varactor is a function of the capacitances of the component sub-varactors. The number of varactors and the bias voltages can be configured, so that respective non-linear capacitive responses of the component sub-varactors effectively combine to yield a substantially linear capacitive response for the staggered-bias varactor as a whole.

Methods and devices providing Positive Logic biasing schemes for use in a digitally tuning capacitor in an integrated circuit device are described. The described methods can be used in integrated circuits with stringent requirements in terms of switching time, power handling, noise sensitivity and power consumption. The described devices include DC blocking capacitors arranged in series with stacked switches coupled to RF nodes. The stacked FET switches receive non-negative supply voltages through their drains and gates during the ON and OFF states to adjust the capacitance between the two nodes.

A method and circuit for linearizing a frequency response of an oscillator controlled by a plurality of capacitor banks are disclosed. In the disclosed method, for each capacitor bank of at least two capacitor banks of the oscillator, a respective sensitivity characteristic of the capacitor bank is determined. Further, a set of reference output frequency control words (FCWs) for an associated set of frequencies of the oscillator are determined. When an input FCW is received and an output FCW is responsively provided based on (i) an interpolation between two reference output FCWs of the set of reference output FCWs and (ii) the respective sensitivity characteristics of the at least two capacitor banks of the oscillator. The output FCW is then applied to the at least two capacitor banks of the oscillator.

An oscillator includes a voltage-controlled oscillator (VCO) circuit and a processing circuit. The VCO circuit generates an oscillating frequency according to a digital signal, in which the oscillating frequency is a first oscillating frequency if the digital signal has a first signal value. The processing circuit determines a second signal value of the digital signal according to the first oscillating frequency and a target oscillating frequency, in order to tune the oscillating frequency to a second oscillating frequency. The processing circuit performs an interpolation operation according to a first frequency difference value between the target oscillating frequency and the first oscillating frequency and a second frequency difference value between the second oscillating frequency and the first oscillating frequency to determine a target signal value of the digital signal, in order to adjust the oscillating frequency to the target oscillating frequency.

Provided is a voltage-controlled oscillator capable of suppressing performance deterioration due to a leak current of a variable capacitive element. Each of the first capacitive circuit and the second capacitive circuit includes a variable capacitive element, a capacitive element, a detection circuit, and a compensation circuit. The variable capacitive element is provided between nodes. A capacitance value of variable capacitive element depends on a voltage value between the nodes. The detection circuit applies a bias voltage value to the second node, and detects an amount of leak current flowing through the variable capacitive element. The compensation circuit causes a current for compensating for the leak current of the variable capacitive element to flow through the first node on the basis of a detection result of the detection circuit.

An oscillating circuit has an injection-locked oscillator (ILO) and a calibration circuit. The ILO has a Gm cell and an LC tank. A first node of the Gm cell receives a first injection signal, and a second node of the Gm cell receives a second injection signal. The first injection signal and the second injection signal are differential signals. The Gm cell provides a negative resistance between a first output end and a second output end of the Gm cell. When the calibration circuit tunes a resonant frequency of the LC tank of the ILO, the magnitude of the negative resistance is reduced to control the ILO to stop self-oscillating. After finishing tuning the resonant frequency of the LC tank, the calibration circuit controls the ILO to start self-oscillating by increasing the magnitude of the negative resistance.

A resonant tank includes a first capacitor formed on a semiconductor substrate, a first inductor formed on the semiconductor substrate, a second capacitor formed on the semiconductor substrate, and a second inductor formed on the semiconductor substrate. The first capacitor, the first inductor, the second capacitor, and the second inductor are connected in a ring configuration, with each capacitor connected between a pair of the inductors and with each inductor connected between a pair of the capacitors. An amplifier circuit is coupled to the resonant tank and configured to amplify a signal in the resonant tank.

A voltage-controlled oscillator (VCO) having an operating frequency dependent on a total capacitance of selectable tuning capacitors can be fabricated within an integrated circuit (IC). The VCO can include active electronic devices fabricated within a set of lower layers of the IC and selectable tuning capacitors having electrically conductive structures separated by dielectric material fabricated within a set of upper layers of the IC. The upper layers of the IC are located above the set of lower layers of the IC. The VCO can also include a set of interconnect structures configurable to select a total capacitance of the selectable tuning capacitors by electrically interconnecting the first portion of the VCO to capacitors of the at least one selectable tuning capacitor.

An oscillator architecture with pulse-edge tuning to control the pulse rising and falling edges (such as for duty cycle correction), including a signal generator with a pull-up PMOS transistor coupled to a high rail, and a pull-down NMOS transistor coupled to a low rail. Pulse-edge tuning circuitry includes a high-side tuning PMOS transistor between the high rail and a source terminal of the pull-up PMOS transistor, and a low-side tuning NMOS transistor between the low rail and a source terminal of the pull-down NMOS transistor. Both tuning FETs are controlled for operation as a variable resistor by respective high-side and low-side DACs to provide tuning control signals to the tuning FETs. In an example application, the oscillator design is adapted for a direct conversion RF signal chain (TX and/or RX) including an I-Path and a Q-Path: the signal generator generates I and Q differential signal frequencies.