An exemplary tunable circuit includes an inductor coupled to a node and a first capacitor coupled to the node. The tunable circuit also includes a variable capacitor coupled to the node, such that a total capacitance of the tunable circuit depends on a fixed capacitance of the first capacitor and a variable capacitance of the variable capacitor. In an example, the inductor and the first capacitor are both included in a passive device and the variable capacitor is in a semiconductor device. The variable capacitor allows the total capacitance to be modified for the purpose of, for example, calibrating the capacitance to account for manufacturing variations, and/or adjusting to a frequency range of operation used by wireless devices in a region of the world. The first capacitor may be a higher quality capacitor providing a larger portion of the total capacitance than the variable capacitor.

An exemplary tunable circuit includes an inductor coupled to a node and a first capacitor coupled to the node. The tunable circuit also includes a variable capacitor coupled to the node, such that a total capacitance of the tunable circuit depends on a fixed capacitance of the first capacitor and a variable capacitance of the variable capacitor. In an example, the inductor and the first capacitor are both included in a passive device and the variable capacitor is in a semiconductor device. The variable capacitor allows the total capacitance to be modified for the purpose of, for example, calibrating the capacitance to account for manufacturing variations, and/or adjusting to a frequency range of operation used by wireless devices in a region of the world. The first capacitor may be a higher quality capacitor providing a larger portion of the total capacitance than the variable capacitor.

Devices and methods for improving voltage handling and/or bi-directionality of stacks of elements when connected between terminals are described. Such devices and method include use of symmetrical compensation capacitances, symmetrical series capacitors, or symmetrical sizing of the elements of the stack.

Devices and methods for improving voltage handling and/or bi-directionality of stacks of elements when connected between terminals are described. Such devices and method include use of symmetrical compensation capacitances, symmetrical series capacitors, or symmetrical sizing of the elements of the stack.

A power line communication device including a current path provided between a first terminal and a second terminal. A coupling circuit includes a first circuit of a first inductor connected in parallel with a first capacitor and a first resistor, wherein the coupling circuit is connected between the first and second terminals. A sensor is configured to sense a communication parameter of the coupling circuit. The communication parameter may be a resonance of the first circuit, the quality (Q) factor of the resonance, the bandwidth (BW) of the coupling circuit, the resistance of the first resistor, or the impedance of the first circuit. A transceiver is adapted to couple to the first and second terminal to transmit a signal onto the current path or receive a signal from the current path responsive to the parameter of the coupling circuit and a level of current in the current path sensed by the sensor.

A radio frequency (RF) circuit includes a tank circuit having a selectively variable impedance. The RF circuit further includes a tuning circuit adapted to dynamically vary the impedance of the tank circuit, and to develop a first quantized value representative of a change to impedance of the tank circuit. The RF circuit further includes a detector circuit adapted to develop a second quantized value representative of a field strength of a received RF signal.

A radio frequency (RF) circuit includes a tank circuit having a selectively variable impedance. The RF circuit further includes a tuning circuit adapted to dynamically vary the impedance of the tank circuit, and to develop a first quantized value representative of a change to impedance of the tank circuit. The RF circuit further includes a detector circuit adapted to develop a second quantized value representative of a field strength of a received RF signal.

Methods and apparatuses for use in tuning reactance are described. Open loop and closed loop control for tuning of reactances are also described. Tunable inductors and/or tunable capacitors may be used in filters, resonant circuits, matching networks, and phase shifters. Ability to control inductance and/or capacitance in a circuit leads to flexibility in operation of the circuit, since the circuit may be tuned to operate under a range of different operating frequencies.

Methods and apparatuses for use in tuning reactance are described. Open loop and closed loop control for tuning of reactances are also described. Tunable inductors and/or tunable capacitors may be used in filters, resonant circuits, matching networks, and phase shifters. Ability to control inductance and/or capacitance in a circuit leads to flexibility in operation of the circuit, since the circuit may be tuned to operate under a range of different operating frequencies.

A passive wireless temperature sensor includes a radio frequency (RF) front end having a variable input impedance. The RF front end includes an antenna operable to receive an RF signal having a particular carrier frequency and a tuning circuit having a resonant frequency corresponding to the particular carrier frequency. The passive wireless temperature sensor further includes one or more temperature sensing elements coupled to the RF front end. When sensing a temperature, the one or more temperature sensing elements cause a change in the variable input impedance. The passive wireless temperature sensor further includes a processing module operably coupled to the RF front end operable to adjust the resonant frequency of the tuning circuit to compensate for the change in the variable input impedance and generate a coded value representative of the change. The coded value representative of the change corresponds to the sensed temperature.