Abstract: A low-noise amplifier circuit includes a MOS transistor in a common gate amplifier configuration. A single-ended input is at a source of the MOS transistor. A resonant cavity filter circuit is coupled to a gate of the MOS transistor.

Abstract: A digital amplifying apparatus includes a positive-phase amplifier, an inverting amplifier, a pair of LPFs, a positive and a negative noise component extracting unit, and noise component coupling units that couple a negative and a positive noise component extracted by the negative and the positive noise component extracting units with a positive and a negative PWM signals.

Abstract: An electrical component includes an amplifier that includes an output stage, and a power-supply path for powering the output stage. The power supply path includes a line that includes conductor track sections in parallel. The electrical component also includes a carrier substrate containing the amplifier and the line with the conductor tracks.

Abstract: Described herein are multi-band LNAs that reuse inductors for different frequency bands to minimize chip area. In an embodiment, a multi-band LNA is capable of operating in a narrowband (NB) and a wideband (WB) while reusing at least one input impedance matching inductor and at least one load inductor for both bands. The reuse of inductors results in a more efficient use of chip area. In an exemplary embodiment, the LNA comprises a common source transistor and a common gate transistor. In this embodiment, the LNA operates in a common source configuration using the common source transistor to amplify input signals in the NB, and operates in a common gate configuration using the common gate transistor to amplify input signals in the WB. The LNA reuses an input impedance matching inductor and a load inductor in both configurations, and thus both bands.

Abstract: Disclosed is a novel design of a fully integrated UWB transmitter. The transmitter includes a pulse generator, a pulse modulator, and an ultra-wideband drive amplifier. A new low voltage low power pulse generator circuit is disclosed which can be fully integrated in CMOS or BiCMOS process. This circuit includes a squaring stage, an exponential stage, and a second-order derivative stage. Based on this, PPM, BPSK and PAM pulse modulator circuits and system are disclosed. The modulated pulse is symmetrical second-order derivative Gaussian pulses with a bandwidth up to 5 GHz and having sufficient swing for UWB applications. An ultra-wideband driver amplifier is proposed to amplify the modulator output and drive the antenna. For the driver amplifier, common source resistor and inductor shunt feedback with current reuse technique is employed to achieve the ultra-wideband bandwidth, high gain, and providing matching for the antenna simultaneously.

Abstract: In a broadband communication system there are multi-stage power amplifier systems for amplifying the power of radio-frequency (RF) communication signals. Each stage of the amplifier system results in composite triple beat (CTB) distortion, and if the phase of the CTB distortions are approximately the same (i.e. are in-phase), then the amplitudes of the distortions are added (i.e. “20 dB” rule). The amplifier system of the invention includes one or more phase filters positioned in series between the power amplifier stages. The phase filters are adapted to shift the phase of the communication signals, so that the phase of CTB distortions, resulting from the amplification of the communication signals in the amplifier stages between the phase filters, are substantially different (i.e. are out-of-phase). Thus, only the power of the CTB distortions are added (i.e. “10 dB” rule).

Abstract: An IQ-modulator pre-distorter includes an iteratively updated digital filter (gQ0, gQ1) for filtering one of the branches of an IQ-signal to compensate for IQ-modulator generated amplitude errors. An iteratively updated digital filter (cQI0, cQI1), cross-connected from one of the branches to the other branch, filters one of the components of an IQ-signal to compensate for IQ-modulator generated inter-modulation between the branches. Iteratively updated compensators (dcI, dcQ) counteract IQ-modulator generated offset errors.

Abstract: A bias voltage is applied via a first resistance to the base of a first transistor, and a radio frequency signal is input via a first capacitor to the base of the first transistor. The bias voltage is applied via a second resistance to the base of a second transistor. The bias voltage is applied via a third resistance to the base of a third transistor, and the radio frequency signal RF is input via a third capacitor to the base of the third transistor. A first band rejection filter is provided between the base of the first transistor and the base of the second transistor. A second band rejection filter is provided between the base of the second transistor and the base of the third transistor. The collectors of the first to third transistors are connected in common and the emitters thereof are all grounded.

Abstract: Aspects of the disclosure can provide a bandpass transconductance amplifier that can include a minuend transconductance amplifier that converts a voltage signal to a first current and a subtrahend transconductance amplifier that converts the voltage signal to a second current having substantially the same amplitude as the first current but opposite polarity in both a first and a second stopband. The second current can have a substantially smaller amplitude than the first current in a passband. The disclosed bandpass transconductance amplifier can also include a controller that can tune the passband and the stopbands and a summing circuit that can add the first current and the second current.

Abstract: An n-stage RF choke comprises a series connection of two or more inductors connected in series between a source and a load. The inductor closest to the source has the largest inductance and the inductance closest to the load has the smallest inductance. The inductances of any inductors between the inductor closest to the supply and the inductor closest to the load decrease as a function of distance from the supply. The junctions between the inductors in the series connection are shunted to ground by capacitors connected in series with resistors that provide a matched termination for increasing bandwidth by lowering circuit Q factors and eliminating resonant frequencies. The capacitor closest to the supply has the largest capacitance and the capacitor closest to the load has the smallest capacitance. Any intermediate capacitors decrease in capacitance as a function of distance from the supply. Such an arrangement provides a high impedance that isolates the load from the supply at a wide range of frequencies.

Abstract: An amplifier with integrated filter (e.g., an LNA) is described. In one design, the amplifier may include a gain stage, a filter stage, and a buffer stage. The gain stage may provide signal amplification for an input signal. The filter stage may provide filtering for the input signal. The buffer stage may buffer a filtered signal from the filter stage. The amplifier may further include a second filter stage and a second buffer stage. The second filter stage may provide additional filtering for the input signal. The second buffer stage may buffer a second filtered signal from the second filter stage. All of the stages may be stacked and coupled between a supply voltage and circuit ground. The filter stage(s) may implement an elliptical lowpass filter. Each filter stage may include an inductor and a capacitor coupled in parallel and forming a resonator tank to attenuate interfering signals.

Abstract: Power amplifier (PA) apparatus that includes: a PA device operating at a fundamental frequency and having a maximum operating frequency that is higher than the fundamental frequency, an output current having a fundamental component at the fundamental frequency and a plurality of harmonic components at different harmonic frequencies of the fundamental frequency, and an output voltage based on the output current; a first matching circuit coupled to the PA device and corresponding to the fundamental component; and a second matching circuit coupled between the PA device and the first matching circuit and corresponding to at least one of the harmonic components, wherein the first and second matching circuits maintain the PA output voltage at a value that is no more than a predetermined maximum value, which is less than a breakdown voltage for the PA device.

Abstract: A radio frequency (RF) application circuit is provided. In the RF application circuit, a pair of bipolar junction transistors (BJTs), instead of N-channel metal-oxide-semiconductor (NMOS) transistors, is composed of a switch-block operated in a reversion saturation region. The RF application circuit is used to serve as either an oscillator or a band pass amplifier according to the circuit characteristic of an active circuit. Thereby, not only the function of the conventional NMOS transistor served as a switch can be achieved by the switch-block, but also the element size, turned-on resistance value and turned-off parasitic capacitance value of the switch-block, and the power consumption of the RF application circuit thereof can be reduced. Thus, the resolution of the capacitance unit in a LC resonance circuit and the performance of the RF application circuit thereof can be promoted.

Abstract: A cascode-connected transistor includes a common-source transistor which receives an input signal, and a common-gate transistor which is connected to a drain terminal of the common-source transistor and outputs an output signal. A band-pass filter receives the output signal of the cascode-connected transistors. An adjustment circuit is interposed between the drain terminal and the gate terminal of the common-gate transistor, and adjusts the output impedance of the cascode-connected transistor.

Abstract: Disclosed is a power amplification apparatus in a communication system. The apparatus includes a high power amplifier for amplifying an input signal; and a lattice panel, one surface of which is in contact with a ground plane of the high power amplifier, the one surface including a first line and a second line. The first line has at least two first etched portions and at least one first copperplate portion, the first copperplate portion being positioned between the first etched portions, and the first copperplate portion being formed at an interval of ?0/4, and the second line has at least two second etched portions and at least one second copperplate portion, the second copperplate portion being positioned between the second etched portions, and the second copperplate portion being formed at an interval of ?0?/4.

Abstract: A power amplifying device includes a stabilizing circuit between an input terminal and an amplifier. The stabilizing circuit has a first line, a second line, and a third line. The first line is connected to the ground. The length of the first line is equal to or longer than three fourths of the wavelength of the operating frequency.

Abstract: The present disclosure relates generally to systems and methods for direct current (DC) correction in wireless devices. In one example, a method includes setting a cutoff frequency of a filter at a first frequency, where a signal entering the filter is attenuated based on the cutoff frequency. If a qualified change is detected in a DC component of the signal, the cutoff frequency is set at a second frequency that attenuates more of the signal than the first frequency for a defined time period. The cutoff frequency may then be set to the first frequency after the defined time period.

Abstract: A circuit for broadband amplification is provided. The circuit includes an input HF_IN and an output HF_OUT, a first 90° hybrid coupler being connected to the input HF_IN of the circuit and a second 90° hybrid coupler being connected to the output HF_OUT of the circuit, and two amplifier stages being connected in parallel between the first and the second 90° hybrid coupler, the 90° hybrid couplers being hybrid couplers having an operating range of 1/n octaves between a lower frequency value and an upper frequency value, n?N\{0}, i.e., n is an element of the natural positive whole numbers in such a way that the upper frequency value is greater than the lower frequency range and simultaneously less than two times the value of the lower frequency range, and the amplifier stages being based on transistors having a III-nitride, or SiC, or diamond basis.

Abstract: When switching over from a portable telephone system of 800 MHz band to a UWB communication system of 9 GHz band, depending upon a signal for changing over a high pass filter and a low pass filter, a reactance element, which is determined to be matching with a load Z of the high pass filter, is connected to an output terminal of a transmitting power amplifier. With this, it is possible to achieve a multi-band or multi-mode wireless receiver of using a frequency band from 800 MHz to 10 GHz, without an enlargement of a circuit scale and an increase of costs.

Abstract: An operational amplifier circuit 5 of the present invention includes: a transconductance amplifier circuit 1 which converts a differential input voltage into a differential output current; a common-mode feedback circuit 2 which outputs a control signal to the transconductance amplifier circuit 1 so as to make a D.C. voltage level of a differential output voltage of the transconductance amplifier circuit 1 equal to a reference voltage vref; a voltage supply circuit 3 which supplies, as the reference voltage vref, a voltage which is hardly affected by a power source voltage to the common-mode feedback circuit 2; and an output load ZL to which the differential output voltage of transconductance amplifier circuit 1 is applied, and which constitutes an output terminal of the operational amplifier circuit 5. To each of the circuits, a power source voltage vdd is supplied from a power source terminal.

Abstract: An amplification circuit connected with a lowpass filter, which reduces the time required for compensating the amplification characteristic and starting up at turning on the power supply, and a control method thereof are provided. An amplification circuit 10, which operates in any one of the operation mode of ordinary operation mode MDN and special operation mode MDT, includes an amplifying section 20, a lowpass filter 30 connected to the amplifying section 20, and a lowpass filter setting section 40 that sets a cut-off frequency fc. In the case of an ordinary operation mode MDN, the cut-off frequency is set to an ordinary cut-off frequency fcn in which error in the output signal does not exceed an output allowable error as an allowable error, and in the case other than that, set to the side higher than the ordinary cut-off frequency fcn.

Abstract: A radio frequency power amplifier and corresponding methods are arranged and configured to drive or provide a radio frequency signal to a resonant load. The amplifier includes a radio frequency switching stage with an output that is coupled to a resonant circuit and configured to provide an output signal with amplitude modulation corresponding to amplitude modulation of an input signal when powered from a fixed voltage power supply and a feedback control system coupled to the input signal and the output signal. The feedback control system includes a sequencer configured to provide a sequencer output that is used to drive the radio frequency switching stage, where the sequencer output has an OFF state that begins at a variable time corresponding to the input and output signal.

Abstract: A frequency agile sequential amplifier circuit that includes first and second RF amplifiers coupled by a SAW delay line, a double balanced mixer coupling the first RF amplifier to the SAW delay line, the output of the first RF amplifier providing a signal as a first input to the double balanced mixer and a variable pulse generator coupled to both said first and second RF amplifiers to cause them to sequentially and alternately conduct, and a divide/2 circuit coupling said variable pulse generator to said double balanced mixer as a second input at ½ the rate of said RF amplifiers to cause the sequential amplifier circuit to achieve frequency agility and to substantially maintain its sensitivity.

Abstract: The present invention discloses a bandpass amplifier having gain and bandpass performance. The bandpass amplifier includes an input match unit for matching the gain of the amplifier and having a first filter response; a first bias unit electrically connected to the input match unit for driving the first terminal of the amplifier and having a first high pass filter response; a gain stage electrically connected to the first bias unit for providing the flat gain of the amplifier; a second bias unit electrically connected to the gain stage for driving the second terminal of the amplifier and having a second high pass filter response; and an output match unit electrically connected to the second bias unit for matching the gain of the amplifier and having a second filter response.

Abstract: A circuit and method for electronically tuning an RF power amplifier. The output filter includes at least one electronically variable reactance. The electronically tuned power amplifier may be tuned rapidly to a selected frequency, to a selected impedance, or to produce a selected output amplitude. An optional controller translates frequency, impedance, or modulation inputs into tuning signals. High-efficiency, wideband amplitude modulation is produced by varying the amplifier load impedance along preferred loci.

Abstract: The present invention discloses a gain amplifier, capable of concurrently operating at three different frequency bands. The gain amplifier comprises an amplification stage for amplifying a signal applied to an input of the amplifier and a triple-band resonance load connected between a DC bias voltage and a DC bias input of the amplification stage. The triple-band resonance load uses a set of reactive elements to provide match in a first frequency band, a second frequency band and in a third frequency band, such as at 2.4 GHz, 5.8 GHz and 9.0 GHz. According to the gain amplifier of the present invention, it can effectively provide triple-band signal amplification and in-band interference suppression for various multi-standard coexist communication systems.

Abstract: An amplifier comprising a field effect transistor, a terminating network comprising inductors connected in series separated by capacitors connected in parallel, a filter and a load, wherein the values of the capacitors and inductors are arranged to present open circuits to a predetermined number of odd harmonics of a signal frequency being amplified, and to present short circuits to a predetermined number of even harmonics of the signal frequency, wherein the normalised values of the inductors and capacitors of the terminating network are selected using the following procedure: Let gr=Cr r odd=Lr r even then g1=1, g1g2=(a); grgr+1=(b), r=2?2m?1 and g2mg2m+1=(c) where (m?1) represents the predetermined number of odd harmonics which are presented with an open circuit 1 m ? ( 2 ? m - 1 ) ( a ) 4 ( 2 ? m - 1 + r ) ? ( 2 ? m - r ) ( b ) 1 m .

Abstract: The power amplifier device comprises one or more transistors (16) with an output electrode and on top of that a thin-film capacitor. The capacitor comprises a first conductive layer (18), that is also the output terminal of the transistor. It further comprises a first dielectric layer (20) and a second conductive layer (22), that is connected by at least one first connecting wire (30) to said first conductive layer (18). A second connecting wire (34) connects said second conductive layer (22) to an output terminal of the power amplification device (40). In this manner a parallel LC circuit is created, and it is designed such that said parallel LC circuit shows resonance at a harmonic of a frequency (2Fo, 3Fo, 4Fo, 5Fo and so on) amplified by said power amplifier.

Abstract: In order to provide an interface circuit, a power converter using the same and an electric vehicle using the same, wherein this interface circuit ensures improved control reliability without employing a photo-coupler, an interface circuit 100A transfers control signals to the power transistor in a large-current circuit 300 from a small-signal circuit 200 for driving a power transistor. The interface circuit 100A has a noise absorber 120 that electrically absorbs a noise voltage produced between the ground of the small-signal circuit 200 and that of the power transistor. The noise absorber 120 transfers to the power transistor the control signals generated by the small-signal circuit 200, without being affected by the noise voltage if produced.

Abstract: Disclosed are methods and circuit configurations for reference frequency signal distribution circuitry that suppress unwanted spurious components introduced by way of RF signal leakage. The methods and circuitry may include relocating components of a buffer along a reference frequency signal path, thereby suppressing conductive and inductive components associated with RF leakage paths entering the circuitry. A filter also may be used after the buffer to suppress spurious components resulting from subsampling of unwanted tones in a phase frequency detector or intermodulation between the reference signal and interference tones in the signal-path of the buffer.

Abstract: A power amplifier comprising input means for receiving signals at a plurality of different frequencies; a power transistor for amplifying received signals; first circuitry connected at one end to said power transistor and at another end to a relatively low frequency shorting circuitry, said first circuitry being such that said another end is an open circuit to said different frequencies, said first circuitry having a length which is substantially less than a quarter wavelength of said different frequencies.

Abstract: An amplifier circuit has an amplifier, a D.C. bias circuit, and an output signal path. The amplifier amplifies a modulated signal that has a carrier frequency. The D.C. bias circuit has a decoupling capacitor that is coupled to a transmission line having a length equal to N times the wavelength of the carrier frequency divided by four, where N is an odd integer. A low frequency decoupling capacitor is located between the decoupling capacitor and the output of the amplifier to reduce intermodulation distortion products. In one embodiment, the low frequency decoupling capacitor is a tantalum capacitor.

Abstract: An RF power amplifier having reduced memory effects is disclosed. This is achieved by a novel design of the DC supply feed network to achieve low impedance across video frequencies, whilst maintaining the correct RF output matching. One or more transmission zeros are provided in the bias circuit transfer function, which are positioned in the video bandwidth so as to provide low and relatively constant impedance across the video bandwidth. Also, a parallel DC feed line may be employed to reduce impedance across the video bandwidth. The reduction in memory effects allows improved performance of predistortion linearization techniques and an implementation in a feed forward amplifier employing predistortion linearization is also disclosed.

Abstract: A method and an apparatus for analyzing performance of a multi-stage radio frequency amplifier are described. The method simplifies the multi-stage radio frequency amplifier into equivalent input parts, output parts and mid-stage parts. The mid-stage parts are temporarily unset. Therefore, the equivalent input parts and output parts will be adjusted to make best gain performance and the mid-stage parts will be the next targets for analysis. Repeating the above-mentioned methods for decomposing the circuit can systemize the method for analyzing circuits and problems in each part of the circuit may be found more quickly.

Abstract: A GPS-cellular hand-set includes a receive antenna; a separate transmit antenna; a power amplifier; a duplex filter unit having an input connected to the receive antenna, a cellular output, and a GPS output; a cellular unit having a receive input and a transmit output, wherein the receive input is connected to the cellular output of the duplex filter unit and the transmit output is connected to the transmit antenna via the power amplifer; and a GPS unit having an input connected to the GPS output of the duplex filter unit.

Abstract: A radio-frequency power amplification circuit includes a transistor and a stablization circuit that is provided upstream of the transistor. The stabilization circuit includes a series resistor, a first end of which is connected to the transistor and a second end of which is connected to an input terminal, a resistance element, a first end of which is connected to the second end of the series resistor, and a short stub, a first end of which is connected to the second end of the resistance element and the second end of which is grounded via a capacitance element.

Abstract: An FET band amplifier for providing a high gain. An FET band amplifier 5 included in an AM receiver comprises amplifiers 11 to 15 e.g. at five stages and a BPF 16 inserted halfway in their connection. Each of the amplifiers 11 to 15 acts as a differential amplifier comprising a p-channel FET as an amplification element. The BPF 16 allows the passage of a component of a band wider than the amplification band of the whole of the FET band amplifier and reduces a 1/f noise by removing the low-band component of a signal amplified by the amplifiers 11 to 13 at three stages and thermal noise by removing the high-band component. Thus, each of the amplifiers 14, 15 connected to the rear stage of the BPF 16 is not saturated by a noise component.

Abstract: A predistortion circuit has an input terminal for inputting a predetermined signal; a nonlinear device directly or indirectly connected to the input terminal; a bias supply circuit for applying a voltage to the nonlinear device; specific-frequency suppressing means connected to one side or both sides of the nonlinear device directly without another intervening device and of suppressing all or part of such frequencies that are from a frequency corresponding to DC to a frequency corresponding to an occupied band width of an input signal inputted to the input terminal and/or suppressing at least one higher harmonic frequency of a carrier wave of the input signal; and an output terminal for outputting a signal.

Abstract: Acoustic resonators such as surface acoustic wave (SAW) devices and thin film bulk acoustic resonators (FBAR) can be configured to produce a band reject filter. Such a filter overcomes the insertion loss and power handling limitations of conventional band pass configurations and as such can be used in power amplifier and duplexer applications.

Abstract: An active balun circuit is provided for single-ended to differential RF signal conversion with enhanced common-mode rejection which suppresses common mode signal and which achieves phase and amplitude balance without sophisticated tuning or compensation methods. The circuit has a single-ended input and balanced output with phase and amplitude balance error less than 2° and 1.2 dB, respectively, measured from 1.5 GHz to 1.8 GHz at 5V supply. When supply voltage drops down to 1.5V, its phase and amplitude balance error remains within 5° and 2 dB, respectively. The circuit achieves a balanced output via an output network which behaves as an impedance matching network for differential mode signal and is grounded for common mode signal. As a result, common mode signal is suppressed and 180-degree phase balance at output is achieved. The circuit has high-linearity (P1 dBin=5 dBm, IIP3=16.

Abstract: An RF generating system operates with high efficiency to supply RF output power to a plasma load. The RF generating system is capable of modulating the RF output power at frequencies up to the frequency of the RF output power while maintaining high efficiency operation. Broadband frequency modulation of the RF output power suppresses instabilities thereby minimizing unstable behavior of the plasma load.

Abstract: A technique for minimizing the effect of parasitic capacitance in a resistive gain amplifier. Instead of the resistors being formed directly over the substrate, or over an oxide of the substrate, a semiconductor element (e.g., an n-well) is used between the resistor and the substrate. For resistors in the input circuit, this semiconductor element is connected to the voltage input rather than ground. For the resistors in the feedback loop circuit, the semiconductor element is connected to the voltage output of the operational amplifier. The insertion of this semiconductor element provides the ability to programmably connect the parasitic capacitance to somewhere other than ground. By connecting the parasitic capacitance to the voltage input or voltage output, the ground connection is eliminated, eliminating the pole introduced by the parasitic capacitance.

Abstract: A tunable low noise amplifier matching circuit is provided. The matching circuit includes a ferroelectric tunable component. A control signal is applied to the tunable component, changing the component's impedance. This changes the impedance or the noise figure response, or both, of the matching circuit.

Abstract: The invention relates to a system for matching an antenna (ANT) for a wireless communication device, the system comprising: detecting means (4, 5, 12) to detect the matching of the antenna (ANT) and to generate a matching signal on the basis of the detected matching, control means (7) to examine said matching signal, to determine the need for matching, and to generate a control signal on the basis of said matching signal, and antenna matching means (9) to adjust the matching of the antenna (ANT) on the basis of said control signal. The invention relates also to a wireless communication device and a method for matching the antenna of a wireless communication device.

Abstract: Low pass filters at the output stage of a D-class amplifier, in which a high channel separation between adjacent signal amplifying channels, a small size, implementation at a high density can be attained. Induced electromotive forces by a leakage magnetic flux from the adjacent channels are set off by a plurality of pairs of inductors in one low pass filter. The low pass filter of each channel is formed by the same construction and the same circuit. The inductors are arranged in a manner that center axes of coils of the two corresponding pairs of inductors in the adjacent channels are located at vertexes of a rectangular parallelogram, and combinations of the winding directions of the coils of the corresponding inductors of the adjacent channels are set to the same direction and the opposite directions every other inductor.

Abstract: A power amplifier matching circuit is provided. The matching circuit includes a ferro-electric tunable component. A control signal is applied to the tunable component, changing the component's impedance. This changes the impedance of the matching circuit.

Abstract: It is difficult that the impedance of the circuit part on the output side of an amplifying element at the frequency of a modulating wave is lower, and consequently, it is difficult to more effectively use the linearity of the amplifying element. The phase of a signal of the frequency of the modulating wave included in an amplified signal output from a FET is inverted by a difference frequency inverting circuit. The inverted signal of the frequency of the modulating wave and a signal of the frequency of a modulated wave included in an amplified signal output from a FET cancel each other out at the drain of the FET. At the drain end of the FET, the signal of the frequency of the modulating wave included in the amplified signal of the FET and a signal of the frequency of the modulating wave output from the FET cancel each other out.

Abstract: An amplifier circuit apparatus for driving a laser device, the apparatus comprising a multistage amplifier including an output stage, wherein at least one device for band limiting a signal is coupled to the multistage amplifier prior to the output stage.

Abstract: An inter-stage matching circuit 26 comprises a one-stage high pass filter type matching unit 28 and a one-stage low pass filter type matching unit 29 serially connected with each other.

Abstract: A power amplifier circuit includes a power amplifier responsive to a power mode signal, the power amplifier having a power amplifier output node, and a power amplifier load circuit also responsive to the power mode signal, the power amplifier load circuit having a load circuit input node connected to the power amplifier output node. The power amplifier load circuit has a first transmission line coupled between the load circuit input node and a first node, a harmonic filter coupled between the load circuit input node and a common node, a first capacitor coupled between the first node and the common node, and a first switch coupled between the common node and ground, where the first switch is responsive to the power mode signal.