Abstract: An unbalanced linear power amplifier (PA) is disclosed having a quadrature coupler with a 90° phase input port, a 0° phase input port, an output termination port, and a signal output port. Each of the 90° phase input port, the 0° phase input port, the output termination port, and the signal output port have a characteristic resistance (Ro). Also included is a first PA having an output coupled to a 90° phase input port of the quadrature coupler and a second PA having an output coupled to a 0° phase input port of the quadrature coupler. Biasing circuitry provides the first PA and the second PA with a similar gain. A tuning network is coupled between the output termination port and ground. The tuning network has an isolation resistance in series with an isolation inductance, wherein the isolation resistance is between about 0.02*Ro ? and 0.8*Ro ?.

Abstract: A method for making a micro-electro-mechanical systems (MEMS) vibrating structure is disclosed. The MEMS is supported by a MEMS anchor system and includes a single-crystal piezoelectric thin-film layer that has a specific non-standard crystal orientation, which may be selected to increase an electromechanical coupling coefficient, decrease a temperature coefficient of frequency, or both. The MEMS vibrating structure may have dominant lateral vibrations or dominant thickness vibrations. The single-crystal piezoelectric thin-film layer may include Lithium Tantalate or Lithium Niobate, and may provide MEMS vibrating structures with precise sizes and shapes, which may provide high accuracy and enable fabrication of multiple resonators having different resonant frequencies on a single substrate.

Abstract: A power amplifier (PA) system with PA gain correction is disclosed. The PA system includes a PA having a bias voltage input; and electrothermal feedback circuitry coupled to the bias voltage input. The electrothermal feedback circuitry is configured to receive thermal feedback generated by the PA and maintain a substantially constant PA gain by automatically changing a bias voltage level at the bias voltage input based upon the thermal feedback.

Abstract: A charge pump includes an input, an output, and a fixed voltage node; a first capacitor and at least a second capacitor; and a plurality of switches adapted to selectively couple the first capacitor and the at least the second capacitor to the input, the output, and the fixed voltage node. A switch controller is adapted to switch the plurality of switches in response to at least three phase signals to provide fixed gains. A phase generator is adapted to generate the at least three phase signals, wherein at least one of the at least three phase signals has a duty cycle that is different from at least one other of the at least three phase signals. The phase generator is also adapted to adjust the frequency of a clock signal used to generate the at least three phase signals so that a minimum switching frequency is provided.

Abstract: An average load current detector for a multi-mode switching converter is disclosed. The average load current detector includes a sense voltage generator that generates an average sense voltage that is proportional to an average load current delivered by the multi-mode switching converter. Also included is a duty voltage generator that generates an average duty voltage that is proportional to a duty cycle of a pulse width modulation (PWM) signal that controls switching of the multi-mode switching converter. Further included is a comparator adapted to output a detector signal that indicates an operational mode for the multi-mode switching converter to operate in for predetermined load current ranges. A controller receives the detector signal and in response maintains an efficient energy transfer from one supply voltage level to another by transitioning the multi-mode switching converter from the PWM mode to a pulse frequency modulation (PFM) mode or vice versa if necessary.

Abstract: RF PA circuitry and a DC-DC converter, which includes an RF PA envelope power supply and DC-DC control circuitry, are disclosed. The PA envelope power supply provides an envelope power supply signal to the RF PA circuitry. The DC-DC control circuitry has a DC-DC look-up table (LUT) structure, which has at least a first DC-DC LUT. The DC-DC control circuitry uses DC-DC LUT index information as an index to the DC-DC LUT structure to obtain DC-DC converter operational control parameters. The DC-DC control circuitry then configures the PA envelope power supply using the DC-DC converter operational control parameters. Using the DC-DC LUT structure provides flexibility in configuring the DC-DC converter for different applications, for multiple static operating conditions, for multiple dynamic operating conditions, or any combination thereof.

Abstract: Radio frequency (RF) duplexing devices and methods of operating the same are disclosed. In one embodiment, an RF duplexing device includes a transmission port, a receive port, a first duplexer, and a second duplexer. The first duplexer is coupled to the transmission port and the receive port, and is configured to provide a first phase shift from the transmission port to the receive port. The second duplexer is also coupled to the transmission port and the receive port. However, the second duplexer is configured to provide a second phase shift that is differential to the first phase shift from the transmission port to the receive port. By providing the second phase shift so that the second phase shift is differential to the first phase shift, the RF duplexing device can provide isolation through cancellation without needing to introduce significant insertion losses.

Abstract: The present disclosure relates to gate oxide protection circuits, which are used to protect the gate oxides of field effect transistor (FET) elements from over voltage conditions, particularly during situations in which the gate oxides are particularly vulnerable, such as during certain manufacturing stages. Each gate oxide protection circuit may be coupled to a corresponding FET element through corresponding first and second resistive elements, which are coupled to a corresponding gate connection node and a corresponding first connection node, respectively, of the FET element. The gate connection node and the first connection node are electrically adjacent to opposite sides of the gate oxide of the FET element. Each gate oxide protection circuit may protect its corresponding FET element by limiting a voltage between the gate connection node and the first connection node.

Abstract: Acoustic wave devices and methods of coating a protective film of alumina (Al2O3) on the acoustic wave devices are disclosed herein. The protective film is applied through an atomic layer deposition (ALD) process. The ALD process can deposit very thin layers of alumina on the surface of the acoustic wave devices in a precisely controlled manner. Thus, the uniform film does not significantly distort the operation of the acoustic wave device.

Abstract: An apparatus comprises at least one transmit amplifier and rectification circuitry located in the at least one transmit amplifier, which is configured to receive a RF signal and provide a rectified voltage, which is selectably added to a voltage supplied by a battery to generate a DC voltage supply signal that is a function of RF power level. A controller is configured to select between providing the VBAT or the VSupply signal to a transmit switch depending on one or more of a logic state and a mode of operation. An alternate apparatus comprises a charge pump circuit configured to quickly raise a voltage supplied to it and store the output voltage on a capacitor and then either shift a first frequency provided by a charge pump oscillator to a lower second frequency or turn off a charge pump clock to maintain a voltage on the capacitor during a transmit mode.

Abstract: Power amplifier circuitry includes a power amplifier including an input node and an output node, biasing circuitry, a selectable impedance network, and an input capacitor. The input capacitor is coupled to the input node of the power amplifier. The biasing circuitry is coupled to the input node of the power amplifier through the selectable impedance network. The power amplifier is operable in a low power operating mode and a high power operating mode. In the low power operating mode, the biasing circuitry delivers a first biasing current to the input node of the power amplifier, and a first impedance level of the selectable impedance is selected. In the high power operating mode, the biasing circuitry delivers a second biasing current to the input node of the power amplifier, and a second impedance level of the selectable impedance is selected.

Abstract: The present disclosure relates to de-multiplexing at least one RF input signal feeding RF power amplifier circuitry to create multiple de-multiplexed RF output signals, which may be used to provide RF transmit signals in an RF communications system. Output transformer circuitry is coupled to outputs from the RF power amplifier circuitry to provide the de-multiplexed RF output signals, which may support multiple modes, multiple frequency bands, or both. The de-multiplexed RF output signals may be used in place of RF switching elements in certain embodiments. As a result, RF front-end switching circuitry in the RF communications system may be simplified, thereby reducing insertion losses, reducing costs, reducing size, or any combination thereof. Additionally, the output transformer circuitry may provide load line transformation, output transistor biasing, or both to the RF power amplifier circuitry.

Abstract: An architecture for a radio frequency (RF) front-end is disclosed. The architecture for the RF front-end includes a circuit module that includes a plurality of dies partitioned on the circuit module. A plurality of filter banks with individual ones of the plurality of filter banks disposed on each of the plurality of circuit dies is also included. Further included is a plurality of switches having individual ones of the plurality of switches coupled to corresponding ones of the plurality of filter banks and in at least one embodiment a control system is configured to open and close selected ones of the plurality of switches.

Abstract: The present disclosure provides a power amplifier controller for starting up, operating, and shutting down a power amplifier. The power amplifier controller includes current sense amplifier circuitry adapted to monitor a main current of the power amplifier. A bias generator is also included and adapted to provide a predetermined standby bias voltage and an operational bias voltage based upon a main current level sensed by the current sense amplifier circuitry. The power amplifier controller further includes a sequencer adapted to control startup and shutdown sequences of the power amplifier. In at least one embodiment, the power amplifier is a gallium nitride (GaN) device, and the main current level sensed is a drain current of the GaN device. Moreover, the bias generator is a gate bias generator provided that the power amplifier is a field effect transistor (FET) device.

Abstract: Radio frequency (RF) circuitry, which includes a time division duplex (TDD)/frequency division duplex (FDD) driver stage, a TDD final stage, an FDD final stage, and power directing circuitry, is disclosed. The power directing circuitry is coupled between the TDD/FDD driver stage and the TDD final stage, and is further coupled between the TDD/FDD driver stage and the FDD final stage.

Abstract: Radio frequency (RF) duplexing devices and methods of operating the same are disclosed. In one embodiment, an RF duplexing device includes a transmission port, a receive port, a first duplexer, and a second duplexer. The first duplexer is coupled to the transmission port and the receive port, and is configured to provide a first phase shift from the transmission port to the receive port. The second duplexer is also coupled to the transmission port and the receive port. However, the second duplexer is configured to provide a second phase shift that is differential to the first phase shift from the transmission port to the receive port. By providing the second phase shift so that the second phase shift is differential to the first phase shift, the RF duplexing device can provide isolation through cancellation without needing to introduce significant insertion losses.

Abstract: Existing multi-band/multi-mode (MB/MM) power amplifiers (PAs) use separate signal paths for the different covered frequency bands. This results in a large degree of hardware duplication and to a large die size and cost. Solutions that achieve hardware sharing between the different signal paths of MB/MM PAs are shown. Such sharing includes bias circuit and bypass capacitors sharing, as well as sharing front-end stages and the output stage of the PA. Signal multiplexing may be realized in the transmitter or at the PA front-end while the signal de-multiplexing can be realized either in the PA output stage or at the front-end of the output stage. Such circuits can be applied with saturated and linear MB/MM PAs with adjacent or non-adjacent bands.

Abstract: A parallel amplifier and a parallel amplifier power supply are disclosed. The parallel amplifier power supply provides a parallel amplifier power supply signal, which is adjustable on a communications slot-to-communications slot basis. During envelope tracking, the parallel amplifier regulates an envelope power supply voltage based on the parallel amplifier power supply signal.

Abstract: This disclosure relates generally to radio frequency (RF) amplification devices and methods of operating the same. In one embodiment, an RF amplification device includes an RF amplification circuit and a stabilizing transformer network. The RF amplification circuit defines an RF signal path and is configured to amplify an RF signal propagating in the RF signal path. The stabilizing transformer network is operably associated with the RF signal path defined by the RF amplification circuit. Furthermore, the stabilizing transformer network is configured to reduce parasitic coupling along the RF signal path of the RF amplification circuit as the RF signal propagates in the RF signal path. In this manner, the stabilizing transformer network allows for inexpensive components to be used to reduce parasitic coupling while allowing for smaller distances along the RF signal path.

Abstract: A direct current (DC)-DC converter, which includes a parallel amplifier, a radio frequency (RF) trap, and a switching supply, is disclosed. The switching supply includes switching circuitry and a first inductive element. The parallel amplifier has a feedback input and a parallel amplifier output. The switching circuitry has a switching circuitry output. The first inductive element is coupled between the switching circuitry output and the feedback input. The RF trap is coupled between the parallel amplifier output and a ground.