A low noise amplifier (LNA) system for amplifying a plurality of carriers includes a first amplifier circuit that generates a first radio-frequency (RF) output signal by amplifying a first input RF signal corresponding to a first frequency band, the first amplifier circuit having a first input impedance, and a second amplifier circuit that generates a second RF output signal by amplifying the first input RF signal when the system is in a first multi-output mode, a second input impedance of the second amplifier having a first impedance value when the system is in the first multi-output mode. The LNA system further includes a first impedance controller that maintains the second input impedance of the second amplifier circuit at a second impedance value when the apparatus is in a mode other than the first multi-output mode. The second impedance value is substantially the same as the first impedance value.

A wide bandgap voltage reference circuit generates a temperature stable negative bias reference voltage for use in wide bandgap circuits. The reference circuit uses field effect transistor (FET) based source feedback. It can also be used as source feedback in high power high bandgap device applications, where constant current is required over process and thermal variations.

A wide bandgap voltage reference circuit generates a temperature stable negative bias reference voltage for use in wide bandgap circuits. The reference circuit uses field effect transistor (FET) based source feedback. It can also be used as source feedback in high power high bandgap device applications, where constant current is required over process and thermal variations.

An integrated circuit comprises a first amplifier circuit with a push-pull amplifier configured to be calibrated to a low second order distortion. The integrated circuit further comprises a second amplifier circuit with at least one push-pull amplifier, wherein a size ratio between sizes of the transistors is adjustable by adjusting the size of at least one transistor device. The size ratio can be consecutively adjusted to a plurality of values, and for each value, a first output signal of a push-pull amplifier with an applied test signal and a second output signal of a push-pull amplifier without applied test signal, are determined. The size ratio for which a difference between the push-pull amplifier output signals is closest to zero is determined, and the push-pull amplifier of the first amplifier circuit is calibrated in dependence of the determined size ratio.

An integrated circuit comprises a first amplifier circuit with a push-pull amplifier configured to be calibrated to a low second order distortion. The integrated circuit further comprises a second amplifier circuit with at least one push-pull amplifier, wherein a size ratio between sizes of the transistors is adjustable by adjusting the size of at least one transistor device. The size ratio can be consecutively adjusted to a plurality of values, and for each value, a first output signal of a push-pull amplifier with an applied test signal and a second output signal of a push-pull amplifier without applied test signal, are determined. The size ratio for which a difference between the push-pull amplifier output signals is closest to zero is determined, and the push-pull amplifier of the first amplifier circuit is calibrated in dependence of the determined size ratio.

A transformer includes: a primary winding comprising a first port, a second port and a metal layer connected between the first port and the second port, the metal layer comprising a plurality of sections of different electrical lengths and/or characteristic impedances; and a secondary winding electromagnetically coupled with the primary winding, the secondary winding comprising a first port, a second port and a metal layer connected between the first port and the second port, the metal layer comprising a plurality of sections of different electrical lengths and/or characteristic impedances.

A transformer includes: a primary winding comprising a first port, a second port and a metal layer connected between the first port and the second port, the metal layer comprising a plurality of sections of different electrical lengths and/or characteristic impedances; and a secondary winding electromagnetically coupled with the primary winding, the secondary winding comprising a first port, a second port and a metal layer connected between the first port and the second port, the metal layer comprising a plurality of sections of different electrical lengths and/or characteristic impedances.

The embodiments of the invention relate to a radio frequency oscillator, the radio frequency oscillator comprising a resonator circuit resonant at an excitation of the resonator circuit in a differential mode and at an excitation of the resonator circuit in a common mode, wherein the resonator circuit has a differential mode resonance frequency at the excitation in the differential mode, and wherein the resonator circuit has a common mode resonance frequency at the excitation in the common mode, a first excitation circuit configured to excite the resonator circuit in the differential mode to obtain a differential mode oscillator signal oscillating at the differential mode resonance frequency, and a second excitation circuit configured to excite the resonator circuit in the common mode to obtain a common mode oscillator signal oscillating at the common mode resonance frequency.

A power control method and device for improving radio-frequency power amplifier (RF PA) switch spectrum, the method comprising the following steps: (a) detecting the gate voltage and drain voltage, or the gate voltage and supply voltage (vdd) of a pass element (105) to obtain the saturation information of the pass element (105); (b) if the saturation information indicates that the pass element (105) is about to leave the saturation working area, shunting the drain current of the pass element (105) to the error amplifier (102) to reduce the drain output voltage, thus reducing the variation of the output voltage, preventing the output voltage from quickly approaching the supply voltage (vdd), maintaining the saturation of the pass element (105), and improving the switch spectrum characteristics of RF PA.

A power control method and device for improving radio-frequency power amplifier (RF PA) switch spectrum, the method comprising the following steps: (a) detecting the gate voltage and drain voltage, or the gate voltage and supply voltage (vdd) of a pass element (105) to obtain the saturation information of the pass element (105); (b) if the saturation information indicates that the pass element (105) is about to leave the saturation working area, shunting the drain current of the pass element (105) to the error amplifier (102) to reduce the drain output voltage, thus reducing the variation of the output voltage, preventing the output voltage from quickly approaching the supply voltage (vdd), maintaining the saturation of the pass element (105), and improving the switch spectrum characteristics of RF PA.