A band-pass filter (BPF) includes a pair of coupled transformers including first through fourth conductive structures. The first conductive structure includes a first terminal and two first extending portions extending from the first terminal and configured as primary windings. The second conductive structure includes a second terminal and two second extending portions extending from the second terminal. A first via connects the third conductive structure to a first one of the two second extending portions, the third conductive structure and the first one of the two second extending portions thereby being configured as a first secondary winding. A second via connects the fourth conductive structure to a second one of the two second extending portions, the fourth conductive structure and the second one of the two second extending portions thereby being configured as a second secondary winding.

In semiconductor integrated circuitry having metal layers and via layers sandwiched between adjacent said metal layers, a capacitor is formed from metal structures implemented in first to third metal layers. The metal structures comprise strips having widths parallel to the layers. The strips of the first layer form a first comb having a base strip and a plurality of finger strips extending from the base strip, the widths of the strips being in a lower range of widths. The strips of the second layer form a second comb having a base strip and a plurality of finger strips extending from the base strip, the widths of the finger strips being in the lower range of widths. The width of each base strip formed in the second layer is in an intermediate range of widths; and the strips formed in the third layer have widths in a higher range of widths.

Articles including oscillating units and methods for producing the same are disclosed. An example article includes one or more oscillator units, where each oscillator unit comprises: a micro strip transmission line extending from a first end to a second end. A first termination impedance is coupled to the first end and a second termination impedance is coupled to the second end. A first transistor is coupled between the first end and the midpoint; and a second transistor is coupled between the midpoint and the second end. The micro strip transmission line has a midpoint between the first end and the second end; and each oscillator unit generates a standing wave having a predetermined wavelength in the micro strip transmission line.

An oscillator includes a first node having a first bias voltage, a second node having a second bias voltage, and a reference node having a reference voltage. A forward stage includes a first terminal coupled to an output terminal of the oscillator, and a second terminal coupled to one of the first node, the second node, or the reference node. A transformer-coupled band-pass filter (BPF) is coupled between the output terminal and a third terminal of the forward stage.

Examples described herein provide for a relaxation oscillator and corresponding methods of operation. In an example, a circuit includes a dynamically controllable current source, a capacitor, and an oscillator generation circuit. The dynamically controllable current source includes a digitally tunable current mirror configured to generate a current. The digitally tunable current mirror includes multiple transistors configured to be selectively electrically connected in parallel to alter a gain of the digitally tunable current mirror to control the current. The capacitor is selectively electrically connected to the dynamically controllable current source. The oscillator generation circuit is electrically connected to the capacitor. The oscillator generation circuit is configured to generate an oscillation signal in response to a voltage of the capacitor.

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.

An integrated circuit comprising: a substrate; a configurable tank circuit on the substrate, the configurable tank circuit including: a first pair of inductive loops driven in parallel in each of a first configuration and a second configuration, each of the inductive loops in the first pair enclosing a corresponding capacitive element connected in parallel with that inductive loop; a second pair of inductive loops driven in parallel with the first pair of loops in the second configuration, the second pair of inductive loops undriven in the first configuration; and a switch arrangement that alternately places the configurable tank circuit into either of the first and second configurations; and an oscillation driver that drives the configurable tank circuit at a tunable resonance frequency.

The present invention provides a frequency selective circuit. The frequency selection circuit comprises a voltage-controlled oscillator, a frequency divider, a frequency selective unit and a register group, the voltage-controlled oscillator is used to output a frequency corresponding to the frequency adjustment window; the frequency divider is used to divide the clock frequency output by the voltage-controlled oscillator, and to feed back the resulting low frequency to the frequency selection unit; the frequency selective unit is used to compare a reference frequency with the resulting low frequency output by the frequency divider, and to provide the frequency adjustment window which is configured based on the frequency search window to the voltage-controlled oscillator. The register group is used to output the frequency search window which is provided to the frequency selective unit. The embodiment of the present invention discloses a frequency selective circuit, where the clock frequency is provided to the frequency divider, so that, the clock frequency is converted from a high frequency to a low frequency. The low frequency is compared with the reference frequency to ultimately find the corresponding low frequency that has the same frequency as the reference frequency.

In accordance with an embodiment, a method includes: receiving, by an adjustable frequency doubling circuit, a first clock signal having a first clock frequency; using the adjustable frequency doubling circuit, generating a second clock signal having a second clock frequency that is twice the first clock frequency; measuring a duty cycle parameter of the second clock signal, where the duty cycle parameter is dependent on a duty cycle of the first clock signal or a duty cycle of the second clock signal; and using the adjustable frequency doubling circuit, adjusting the duty cycle of the first clock signal or the second clock signal based on the measuring.

An apparatus includes a digitally controlled oscillator (DCO), which includes an inductor coupled in series with a first capacitor. The DCO further includes a second capacitor coupled in parallel with the series-coupled inductor and first capacitor, a first inverter coupled in parallel with the second capacitor, and a second inverter coupled back-to-back to the first inverter. The DCO further includes a digital-to-analog-converter (DAC) to vary a capacitance of the first capacitor.