A semiconductor device includes: a semiconductor substrate whose contour is a pentagon; a front-stage amplifier formed relatively near a vertex of the pentagon of the semiconductor substrate; and a rear-stage amplifier formed relatively near a side opposed to the vertex of the semiconductor substrate and amplifying an output from the front-stage amplifier.

Amplifiers can be used for a variety of electronic-based applications. Therefore, amplifier performance is of importance. A low noise amplifier can be interfaced after an antenna or a band-select filter as a first active stage, in a receiver since its bandwidth characteristics can be closely related to a system data rate. A bandwidth enhancement technique can be leverage for low noise amplifiers by embedding a transformer between a gate and a drain terminal of a common gate transistor in a cascode topology. The embedded transformer can introduce an additional high-frequency conjugate zero pair, which can push the gain rolling-off start-up point to a higher frequency, peak the higher frequency gain, and broaden the low noise amplifier gain bandwidth.

Amplifiers can be used for a variety of electronic-based applications. Therefore, amplifier performance is of importance. A low noise amplifier can be interfaced after an antenna or a band-select filter as a first active stage, in a receiver since its bandwidth characteristics can be closely related to a system data rate. A bandwidth enhancement technique can be leverage for low noise amplifiers by embedding a transformer between a gate and a drain terminal of a common gate transistor in a cascode topology. The embedded transformer can introduce an additional high-frequency conjugate zero pair, which can push the gain rolling-off start-up point to a higher frequency, peak the higher frequency gain, and broaden the low noise amplifier gain bandwidth.

An amplifier comprises a common emitter stage coupled to a first and a second input, a common base stage coupled to the common emitter stage and to a first and a second output, and a cancellation path coupled to the common emitter stage and the common base stage and to the first and second outputs. The cancellation path generates a first cancellation signal that is 180 degrees out of phase with a first leakage signal at the first output and a second cancellation signal that is 180 degrees out of phase with a second leakage signal at the second output. The cancellation path comprises a first cancellation transistor coupled to the common emitter stage and the common base stage and to the first output and a second cancellation transistor coupled to the common emitter stage and the common base stage and to the second output.

The invention relates to a sequential broadband Doherty power amplifier with adjustable output power back-off The sequential broadband Doherty power amplifier has at least one input (I.sub.1, I.sub.2; RF.sub.in) for receiving at least one broadband HF signal, wherein the broadband HF signal or broadband HF signals (RF.sub.in) have at least an average power level (carrier/average) and a peak envelope power level (peak), with the average power level and the peak envelope power level defining a crest factor, and a first amplifier branch for amplifying the input signal, with the first amplifier branch providing the amplification substantially for the low and at least the average power level, at least one second amplifier branch for amplifying the input signal, wherein the second amplifier branch substantially provides the amplification for the peak envelope power level, wherein the output of the first amplifier branch is connected via an impedance inverter (Z.sub.T) to the output of the second amplifier branch, the junction (CN) being connected to the load (Z.sub.0) in a substantially directly impedance-matched manner, wherein the first and the second amplifier branch each have a supply voltage, with at least one of the supply voltages being variable as a function of the crest factor of the signal to be amplified, and wherein the signal propagation delay through the at least two amplifier branches is substantially identical in the operating range.

The invention relates to a sequential broadband Doherty power amplifier with adjustable output power back-off The sequential broadband Doherty power amplifier has at least one input (I.sub.1, I.sub.2; RF.sub.in) for receiving at least one broadband HF signal, wherein the broadband HF signal or broadband HF signals (RF.sub.in) have at least an average power level (carrier/average) and a peak envelope power level (peak), with the average power level and the peak envelope power level defining a crest factor, and a first amplifier branch for amplifying the input signal, with the first amplifier branch providing the amplification substantially for the low and at least the average power level, at least one second amplifier branch for amplifying the input signal, wherein the second amplifier branch substantially provides the amplification for the peak envelope power level, wherein the output of the first amplifier branch is connected via an impedance inverter (Z.sub.T) to the output of the second amplifier branch, the junction (CN) being connected to the load (Z.sub.0) in a substantially directly impedance-matched manner, wherein the first and the second amplifier branch each have a supply voltage, with at least one of the supply voltages being variable as a function of the crest factor of the signal to be amplified, and wherein the signal propagation delay through the at least two amplifier branches is substantially identical in the operating range.

Circuits, methods and devices are disclosed, related to fast turn-on of radio-frequency (RF) amplifiers. In some embodiments, an RF amplifier circuit includes an amplification path implemented to amplify an RF signal, where the amplification path includes a switch and an amplifier. In some embodiments, each of the switch and the amplifier are configured to be ON or OFF to thereby enable or disable the amplification path, respectively. In some embodiments, the RF amplifier circuit includes a compensation circuit coupled to the amplifier, where the compensation circuit is configured to compensate for a slow transition of the amplifier between its ON and OFF states resulting from a signal applied to the switch.

Circuits, methods and devices are disclosed, related to fast turn-on of radio-frequency (RF) amplifiers. In some embodiments, an RF amplifier circuit includes an amplification path implemented to amplify an RF signal, where the amplification path includes a switch and an amplifier. In some embodiments, each of the switch and the amplifier are configured to be ON or OFF to thereby enable or disable the amplification path, respectively. In some embodiments, the RF amplifier circuit includes a compensation circuit coupled to the amplifier, where the compensation circuit is configured to compensate for a slow transition of the amplifier between its ON and OFF states resulting from a signal applied to the switch.

A power amplifier circuit includes a main amplifier circuit having a main amplifier for amplifying an input signal in one of a full-power mode and at least a back-off mode. A first peak amplifier circuit is in parallel with the main amplifier circuit. The first peak amplifier circuit has a peak amplifier in series with a transmission line. The peak amplifier is configured to be activated in the full-power mode and to be de-activated in at least the back-off mode. A combining node is connected to an output of the main amplifier circuit and an output of the transmission line. In some embodiments, a matching network is connected at the output of the combining node. In some embodiments, the transmission line is selected so the first peak amplifier circuit appears substantially as an open circuit to the combining node.

A power amplifier circuit includes a main amplifier circuit having a main amplifier for amplifying an input signal in one of a full-power mode and at least a back-off mode. A first peak amplifier circuit is in parallel with the main amplifier circuit. The first peak amplifier circuit has a peak amplifier in series with a transmission line. The peak amplifier is configured to be activated in the full-power mode and to be de-activated in at least the back-off mode. A combining node is connected to an output of the main amplifier circuit and an output of the transmission line. In some embodiments, a matching network is connected at the output of the combining node. In some embodiments, the transmission line is selected so the first peak amplifier circuit appears substantially as an open circuit to the combining node.